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Concourse 2

Time adjuncts


Time adjuncts get their own guide because this is a complex area of English grammar which is the source of much error and unnatural language produced by learners of English.
Partly, this is because the area is simply complex and difficult to learn and partly because languages differ in how they conceptualise and cut up time.

This guide only considers adjuncts and will include prepositional phrases, adverbs and nouns acting adverbially.  Here are some examples of what's considered below:

  1. adverbs
    She arrived recently
    They spoke briefly afterwards
  2. prepositional phrases
    Since the mid-60s, people have been visiting the island
    He has lived here
    for ages
  3. noun phrases:
    We had a meeting that Monday
    We stayed all week
    (For our purposes below, noun phrases will mostly be referred to simply as adverbials or as the complements in prepositional phrases as appropriate.)

Not included here are subordinate time clauses, except in passing, and they include, for example, structures such as:
    When I had finished lunch, I took the dog for a walk
At the end, there is link to a guide to tenses in subordinate clauses.

We are only considering adverbial adjuncts in what follows, i.e., adjuncts which modify verb phrases.  Adjuncts can also modify, for example, noun phrases as in:
    The argument after dinner was soon settled
in which the adjunct, after dinner, modifies the noun phrase the argument
    She was very happy

in which the adjunct very modifies the adjective happy
    He drove too quickly

in which the adjunct too modifies the adverb quickly.
The technical terms for these sorts of adjuncts are, respectively, adnomial, adadjectival and adadverbial but those are not terms which should delay you or your learners.


An attempt at classifying the variety

There is no profession-wide agreement on how time adverbials can be divided.  This analysis draws on three attempts (all different) and there are lots more to choose from.
The most primitive (and arguably least useful) distinction is to divide the area into two categories:

  1. Adverbials which say when something happens, happened, exists or existed
        He arrived yesterday
        She cleans daily
        I have paid the bill already
  2. Adverbials which say how often something happens, happened, exists or existed
        I never went to school by bus
        The post arrives daily
        He frequently shops at the supermarket
        They scarcely ever have much time for holidays

There is some logic to a crude division like this because of the position in a sentence that the adverbials can occupy.

  1. Group 1 adverbials normally prefer the end position or can be fronted so we can have:
        Yesterday, she visited her aunt
        She visited her aunt yesterday

    but not:
        *She yesterday visited her aunt
        *She visited yesterday her aunt
  2. Group 2 adverbials are different.  There are two sorts of these:
    1. Adverbials of definite (i.e., measurable) frequency
      occur most commonly in the final position in a clause so we see, e.g.:
          The car is serviced yearly
          The train leaves hourly
          The bus arrives at 8 every day

    2. Adverbials of indefinite (i.e., not measurable or approximate) frequency
      can occupy the end position but most frequently occur with the verbs (before main verbs, after auxiliaries).  They can be fronted for emphasis but that is not their normal position at all.  When the adverbial is a phrase, it usually occupies end position so, we can have, for example:
          She frequently works too hard
          Often, I think of retiring
          They have almost never taken the offer
          She argues with her sister from time to time

          They can usually be relied on
      but not:
          *They went frequently out in the evening

For learners of the language, especially at elementary levels, that is a clear and accessible distinction which covers many eventualities.
For teachers, however, for whom this part of the site is written, it won't do, because it would exclude some quite usual forms, such as
    They have already arrived
    I went again to the manager to complain
    I immediately phoned the police

and so on.  These forms are allowable because the adverbial time adjunct is a proper adverb rather than a prepositional phrase.  We cannot put prepositional or noun phrases in the same position in the clause because that produces the unacceptable (or marginally acceptable):
    *They have at this moment arrived
    ?They went at 6 o'clock to the manager
    *I that evening telephoned the police

A related issue is that virtually all time adverbials can, for special emphasis, be placed in the initial position in a sentence so we allow a huge range including:
    Briefly, they spoke about the issue
    Then they left
    Now I want to go
    Scarcely ever do we watch TV
    On my holiday, I went to museum
    Immediately, I spent all the money
    Since the war, she has lived alone
    Nearly always, I take the bus

and so on.
For the sake of the analysis below (and your sanity) we will not analyse these forms separately but simply note here that the initial position is almost always possible but it serves to place emphasis on the adverbial.  It marks it, in other words.
So, when you encounter a rule below, add mentally: except where the speaker / writer chooses to front the adverbial for effect.

Here's a more complicated arrangement which we will use here:

Don't worry, more explanation of the terms in that diagram follows.
This is not a classification that everyone would support and certainly not suggested here as a way forward for all considerations of analysing the area.
However, it is based on principle and, moreover, is a practical way of approaching the topic in the classroom rather than from the perspective of a grammarian.
The shortcomings of this (and any other attempt to classify a slippery area) will become apparent.


Adverb or prepositional phrase?

Website warning:
Out here on the web, you will encounter lists of time adjuncts which promiscuously mix up adverbs proper (such as now, then etc.) and prepositional phrases (such as in the morning, after work etc.) and sometimes noun phrases acting adverbially (such as the following week, today, Tuesday etc..  Usually, they are simply all classified as adverbs rather than the correct term, adverbials.
That way madness lies because prepositional phrases, noun phrases and adverbs often have different syntactical properties and occur in different parts of clauses.
If you don't distinguish in the classroom (although it is not usually necessary to bother learners with the metalanguage), then you will encourage errors such as:
    *He from time to time comes
    *They monthly meet
    *She had the previous week left
    *They at six left

and so on.
Errors like those can be teacher induced simply by failing to analyse what is quite a simple distinction.
Word and phrase class is important.

Prepositional phrases, because they contain a complement (usually a noun phrase) are an open class because there is in theory no limit to the number of nouns in any language.  We can make up new nouns to represent new ideas.  For example, until recently, the expression during the telethon, was an unknown and incomprehensible time adjunct prepositional phrase.  No longer.

Adverbs are also an open class of words but time adverbs are a different matter and it is theoretically possible to come up with an exhaustive list of all the time adverbs in English.  The list wouldn't be very long and would include at least:

afterwards, again, ago, already, always, annually, before, before, beforehand, biannually etc., briefly, constantly, constantly, continually, continuously, daily, earlier, early, enduringly, eternally, eventually, ever, finally, first, first etc., firstly etc., forever, formerly, fortnightly, frequently, generally, hourly, incessantly, infrequently, just, last, lastingly, late, lately, later, momentarily, monthly, never, next, nightly, non-stop, normally, now, occasionally, off and on, often, once, once in a while, originally, permanently, persistently, previously, provisionally, quarterly, rarely, recently, regularly, repeatedly, seldom, since, sometimes, soon, still, subsequently, temporarily, then, today, tomorrow, tonight, twice, usually, weekly, yearly, yesterday, yet

If you would like this list as a PDF document, click here.

That's a list unclassified by function and later we'll be a bit more discerning.

coordinating time


This is simplest category so we'll start here.


Defined points of time

Adverbs (and other adverbials including prepositional and noun phrases) which signal when in time something occurred are a relatively small closed group of words and structures.  They include the words in black in this set of examples:
    He arrived this morning
    She left at 6
    They arrived in the afternoon
    They left before the end
    I want to stop now
    He left then

The adverbs proper in this group, from the opening list above include:

ago, late, now, then, today, tomorrow, tonight, yesterday

Of these, ago is unusual in that it acts prepositionally, demanding a noun-phrase complement but the complement precedes it so we have:
    three weeks ago
    *ago three weeks
It is often classified as an adverb in many grammars but is unusual in that it cannot stand alone.
On this site, we consider it a postposition.  That is to say, it functions like an ordinary preposition but it follows rather than precedes its complement.

The adverb then in this list functions to mean at that time but can also be a sequencer to express the ordering of events (see below).
The words today, tomorrow, tonight, yesterday are often classified as nouns (and so they are in some circumstances such as Yesterday was lovely) and the list could be extended (because nouns are an open class) to include yesterday evening, the coming week, the night before last and so on.

The worthwhile teaching point here is that adverbials which refer to an explicit and definite time are most comfortable and most frequently found at the end of the clause.  It is, naturally, possible in some cases to place them in the middle of the clauses so we might allow:
    I want now to stop
    He then left
but this is rare and rarity implies that the item is marked for some special emphasis.

Moreover, we do not allow prepositional phrases to do this:
    *He this morning arrived
    *She at 6 left
    *They in the afternoon arrived
    *They before the end left
because prepositional phrase time adverbials, as opposed to time adverbs, cannot occupy the middle position in a clause and are normally confined to the end or initial position.

The simple rule of thumb is:

Time adverbials referring to specific moments in time or to defined periods are placed at the end of the clause unless a special meaning is intended.
All time adverbial prepositional phrases are terminal (or initial for emphasis).



There are two basic duration categories:

  1. Adverbials denoting the length of time
    These are related semantically to the set above of explicit time expressions, so we can have:
        He worked from 6 till 11
        They spoke briefly
        They briefly consulted the timetable
        They lived there permanently
        She stayed awhile
        She stayed for a year
        She worked all the following week
        He was temporarily unemployed
        I was momentarily stunned
        He lived here during the 60s
        She lived here during her university course
        She left here months ago
    All these examples refer to a finished action in the past so the verb tense reflects that.
    Prepositional-phrase adverbials and noun phrases like for a year, all month, last year etc. must take the end position but adverbs ending in -ly, such as momentarily, temporarily and briefly can come before the main verb in a medial position.  The safest bet for learners is to place them at the end.
    The rogue here is ago because it is a postposition and follows rather than precedes the noun-phrase complement.
    There is a group of adverbs which fulfil the function of expressing the duration of an event or state and the list includes:

    awhile, briefly, constantly, continually, continuously, enduringly, eternally, forever, incessantly, lastingly, momentarily, non-stop, permanently, persistently, provisionally, repeatedly, temporarily

    but some of these adverbs also carry other meanings (of irritation, determination etc.).  When they do, they follow the same rules as for other adverbs of manner (see the general guide to adverbs linked in the list of related guides at the end, for more).
  2. Adverbials expressing the sense of up to this moment
    Again, there is a limited range:
        I have lived here since 1998
        I have lately been working on a new project
        They have recently got married
        She has worked hard this month
        I have been doing that a lot recently
        I have been here for a month

    The adverbs lately and recently refer to a recent undefined period but strongly imply that the action or state is ongoing.
    Noun phrases acting adverbially always take the end position.
    In prepositional phrases, only since pins the beginning to a specific time and only for is used to express the length of time.
    The preposition during is covered above under the first set and it makes little sense to include it in the teaching of words such as for and since because it operates so differently.
    Note that since is also included in the list of adverbs because it can act as one in expressions such as:
        I saw him last Thursday but not since
    When it fulfils this up-to-now function, it always occurs at the end of a phrase and is probably better analysed as a preposition with an ellipted complement such as then or that time.
    A prepositional phrase adverbial must take the end position but adverbs proper can appear medially or in end position.  The safest bet for learners is to place them at the end.
    Some of these adjuncts are discussed again below under the category of Relational adjuncts because they serve to relate two times and two states or events to each other.



Again, as we saw above and will reiterate here, there are two categories with different syntactical characteristics:


Definite frequency

There are two related and syntactically similar types of adverbial which indicate definite frequency:

  1. To express the period of the frequency, adverbs with -ly suffixes are the usual forms:
        The trains leave hourly
        I pay my road tax monthly
        We meet annually
        The bill is sent out quarterly

    These always take end position in the clause.
  2. To express the frequency of an event, prepositional and noun phrases are common:
        We meet three times a year
        We did it four times
        He was late on five occasions

    but adverbs can also be used
        They did it twice
        They argued again and again

    These also always occupy the end position in the clause.

From the list above, adverbs which fall into the category of definite frequency include:

annually, biannually etc., daily, fortnightly, hourly, monthly, nightly, quarterly, weekly, yearly

and many are derived from nouns although none derives from decade or century.


Indefinite frequency

Indefinite frequency is indicated by what in other analyses and some books for learners are called adverbs of frequency.
Semantically this group can be divided into 4 sections:

  1. The usual:
        He has generally eaten there
        I normally hate travelling by tube
        She habitually argues with me
  2. The continuous or iterative (repeated):
        She has constantly interfered
        They continually complain
        He is perpetually late for work
  3. The frequent:
        I regularly take a bus to work
        She frequently talks to her dogs
        They often eat out
  4. The infrequent (or absent):
        I rarely go to the cinema
        She has never complained
        I seldom meet him
        They will periodically take time off
        They meet from time to time
        He works off and on

When the adverb adjuncts co-occur with other time adjuncts, the medial position is required or more natural:
    I go to the cinema frequently on Saturdays
is allowable but less natural than
    I frequently go to the cinema on Saturdays
    ?They come occasionally late
is very unnatural compared with
    They occasionally come late

Adverbs from the list above which fall into the category of indefinite frequency include:

Single words:
always, constantly, ever, frequently, generally, infrequently, never, normally, occasionally, often, regularly, seldom, sometimes, regularly, usually
at times, every so often, from time to time, now and again, off and on, on and off, on occasion, once in a while

The adverb ever is the odd one out because it is a non-assertive form only appearing in negative and interrogative clauses.  We allow, therefore:
    Do you ever see her?
    I haven't ever seen her

but not
    *I have ever seen her
The multi-word adverbs, like off and on, take the end position in clauses and cannot appear before the verb.  In that sense they are akin to prepositional phrases such as from time to time which can only appear terminally.
Noun phrases cannot refer to indefinite frequency but appear often as the complements of prepositions in, e.g., with constant repetition, with annoying frequency, at all times etc.

All four of the indefinite groups share a syntactic pattern:

Single word adverbs in this category are usually placed before the main verb but after any auxiliary verb and the verbs be and have.
These adverbs can also be used in the end position but that is slightly rarer.
Co-occurrence with other time adverbials usually forces medial position.
Prepositional phrases, noun phrases or multi-word adverbs always take end position.

hand holding

Relational adverbials

A note on tenses:

English has two fundamental tense forms which are reflected in the structures with which the tenses combine and that applies especially to time adjuncts.  These two tense types are:

  1. Absolute tenses
    These refer to specific times in the past, present or future.  For example:
        He went to London last Monday
        They were eating when the postman arrived
        He will take the 4-o'clock train tomorrow
        They applauded loudly at the end of the performance and went on clapping for over 5 minutes

    Adjuncts of both time and duration, yesterday, at 6 o'clock, for an hour, tomorrow etc., are naturally used with absolute tenses, went, will go, were playing etc.
  2. Relational tenses
    These relate two times together and are, traditionally, referred to as perfect aspect forms.  For example:
        He had already finished the work by the time I arrived
        If Mary hasn't shown up yet, we'll put the meeting off for an hour
        By the time you arrive I'll already have left

    With relational meanings we need to deploy somewhat different time adjuncts.  This is not because the time adjuncts require these particular tense forms, as is often averred in coursebooks and grammars for learners, but because the function of the tense forms is to relate times to each other and that leads to the adjuncts which are appropriate to the function.
    To suggest, for example, that the adverb already demands a perfect tense form is to get the direction of causation the wrong way around.  It is in the nature of relational tense forms that they require adverbials which are semantically appropriate.

There are two sorts of relational time adverbials.


Linking events and states

Some of these have been covered above because categories overlap.  The adverbials that link times together and, therefore relate tenses to each other are exemplified here (in black).  The normal linkage occurs between:

  1. A past event or moment in time and the present
  2. The future and beyond the future
  3. The past and before the past

For example:

Prepositional phrases with since are marginal in this respect and probably better analysed under duration (above) because that is their key sense.

Adverbs which fall into this category from the list above include:

already, before, early, earlier, eventually, just, lately, recently, since, soon, still, later, next, previously, yet

There are issues with assertion and non-assertion with still, already and yet, insofar as already is an assertive form and yet and still are non-assertive, appearing in questions and negative statements:
    She still hasn't done it
    Has he done it yet?
    Are you still here?
    They've already arrived


The position of relational adjuncts is quirky and needs careful handling in the classroom:

  1. already and yet
    these are adverbs and, as is common for the word class, often occupy a medial position before the main verb but after auxiliaries rather like indefinite frequency adjuncts (above).
    They can also appear at the end of the clause so both
        She has already made dinner
        She has made dinner already
    are possible although the end position gives the adjunct greater weight and the medial position is more frequent.
    Equally, however,
        They haven't yet done it
        They haven't done it yet
    are both acceptable but the end position is the more natural in informal language.
  2. still
    is an adverb and confined to a medial position immediately after the subject when used non-assertively.  So,
        She still can't see the point
        Can she still be here?
    is acceptable but
        *She can't still see the point
        *She can't see the point still

    are not.
    Assertively, however, there are variations so:
        I may be old but I can still hold a glass straight
        He will still be there when you arrive

        He's working still
    are acceptable and follow the same syntactical pattern as already, recently and lately.
  3. by and by the time
    are prepositional and frequently appear as pseudo-conjunctions.  They are confined to the end position of the first clause.  Otherwise, they simply take the end position because they are prepositional phrases.  So,
        They'll have repaired it by the time you need it
        She'll have got there by now
        We'll have been working on this for six hours by 10 o'clock

    are all acceptable but other positions for the adjuncts are not normally possible:
        *They'll have by the time you need it repaired it
        *She'll have by now got there
        *We'll have by ten o'clock been working on this for six hours
    are all unacceptable.
  4. since
    is also prepositional and assumes it place in the phrase at the end of the clause so,
        I have been waiting for a taxi since half past three
    is fine but
        *I have been since half past three waiting
    is not.
    See above for the times when since acts like an adverb without a complement.


The other form of relational adjuncts serves to link events in time (by, usually, making it clear what happened first).  Unlike the relational forms, they do not necessarily connect times together; they link events and states so are frequently found with absolute rather than relational tense forms.
They are often conjuncts rather than adjuncts proper because they function to link events or actions between sentences or clauses.
In this group come the adverbs and prepositional phrases, firstly, then, at first, in second place etc., which are often referred to as sequencers (imaginatively).
Noun phrases are rarer in this function but nominalised clauses such the second part of the procedure is , the last thing to do is etc. do occur.

Here are some examples of common uses of sequencing adverbials:
    She had dinner before me
    They spoke afterwards
    The first thing that needs to be done is get the facts
    They spoke after the meeting
    Before 6, he had finished
    First, he fed the cat, then he fed himself
    Subsequently, we ran out of time
    He came from America originally

A sub-set of sequencing adjuncts includes those that refer to repetition of an action:
    He did it three times
    She's lost it again
    As before, he wasn't believed

Adverbs which fall into the category of sequencers from the list above include:

afterwards, again, before, beforehand, finally, first, second etc., firstly, secondly etc., formerly, last, lastly, later, once, originally, subsequently, then

These adjuncts can be adverbs, nominalised clauses or prepositional phrases and they almost always occupy initial or end positions.  They are slightly unusual because, as was noted at the outset, the initial position, while being a possible position for all adjuncts, usually emphasises the adjunct in some way.  In the case of sequencers, which are often conjuncts, this is less marked because initial position is the canonical or normal one.


Coordinating time adjuncts

We can coordinate time adjuncts but only when they serve the same function.  We cannot produce coordinated phrases when there is a mismatch between the functions of the items and retain naturalness.

So, for example, the following are all possible because the adjuncts being linked are in the same category:

The following examples are not acceptable in English because there is a mismatch of function between the adjuncts:


Ordering time adjuncts

When time adjuncts occur in the final position in the clause (as most can and nearly all prepositional and noun phrases do), then there is a conventional ordering:
    When (duration) → When (frequency) → When (defined point in time)

It can be set out like this (although it is rare to have examples of all three types of adjunct as in the first two examples):

Event Duration Frequency When
John goes running for an hour every morning before breakfast
We meet over lunch most days at the moment
I was in my office only briefly   today
She walks the dog   very often in the evening
We rent a cottage for a week every Christmas  

It is, naturally possible to move adverbs of frequency to before the main verb (following any auxiliary verbs) but that cannot be done with phrases of frequency.

So, for example, we prefer:
    The flights arrive hourly in the summer
    *The flights arrive in the summer hourly
    He runs for 10 minutes every morning
    *He runs every morning for ten minutes
    We met for an hour or so from time to time in the summer months
    *We met from time to time in the summer months for an hour or so

This is not a hard rule and speakers will often disturb the ordering to mark an adjunct for special emphasis but it is a rule worth following for learners of the language.
If your learners are producing unnatural time phrase ordering it may reflect that fact that languages differ in this respect so it may be worth spending a little time on this issue.

The other minor consideration here is when we have two adjuncts of the same type and then we usually prefer the more exact before the less exact (just as smaller places come before larger in place adjunct ordering).  So, we get
    He came at six on Monday
rather than
    He came on Monday at six


Time and place together

Frequently, time adjuncts and place adjuncts co-occur in the same clause.
In English, there are no absolute rules for ordering time and place (as there are in many languages).  There are, however, rules of thumb:

  1. We place longer adjuncts after shorter ones so we prefer:
        He was working here for many years
    rather than
        *He was working for many years here
        He was working in 1990 at a prestigious and expensive Chinese restaurant in New York
    rather than
        He was working at a prestigious and expensive Chinese restaurant in New York in 1990
  2. When all the adjuncts come at the end of the clause, as is frequently the case, the usual order is place then time because place is considered more intimately associated with the verb phrase, so we prefer:
        He worked at a restaurant in London for three years in the mid-70s
    rather than
        He worked for three years in London, in the mid-70s at a restaurant
    or any other possible combination of the four adjuncts.
  3. When the first two rules conflict and to avoid stylistic problems, the time adjunct is often placed in initial position so the last example might be better as:
        In the mid-70s, he worked at a restaurant in London for three years
        For three years in the mid-70s, he worked at a restaurant in London

For special emphasis or to give one adjunct or another extra weight, speakers will flout these rules so we might get:
    At that time, of course, in London it was difficult to get a decent cup of coffee anywhere.


Modifying time adjuncts

Most time adjuncts can be modified with other adverbials but how it is done depends on the function of the adjunct.

When adjuncts
Defined points of time can be modified with adverbials which make them even more defined, so, for example, we can have:
    He arrived at exactly 6
    They left just then
    He came on the dot of 9

Duration can similarly be modified but it makes a crucial difference whether we are modifying an adverb or a prepositional phrase.  We can have, therefore:
    He was very momentarily embarrassed
    They spoke very briefly
    He has moved here extremely recently

because, in the usual way of things, intensifying adverbs can modify other adverbs.  However, prepositional phrases allow a much more restricted form of modification and it is the noun complement of the phrase which takes the modification:
    He stayed for exactly two hours
    *He stayed exactly for two hours
    He has lived here for a whole year
    *He has lived here whole for a year
Frequency adjuncts
Definite frequency (by its nature) allows the same kind of modification as defined points of time so we can have
    He sends out the bill exactly monthly
    We have been exactly four times
    I have seen her just twice

Indefinite frequency is often signalled by adverbs and these can, in the usual way, be modified, but the modification routinely requires end rather than medial positioning of the adjunct especially if it consists of a phrase:
    They come very frequently
    ?They far too frequently come
    I do that slightly too often
    *I slightly too often do that
The modifiers too and enough (the latter following the adjunct) are available to modify indefinite frequency as in, for example:
    He arrives late too frequently
    She visits too seldom
    They come often enough

etc. but these are not usually acceptable with never and always for semantic reasons (in that one cannot go *frequently always or *seldom never).
Prepositional phrases, again, take different modification usually with only or just:
    They work here only from time to time
    She walks to school just in the summer months
Relational adjuncts
Relational adverbs resist modification.
    *He has absolutely already finished
    *She is not here very yet
    *I have waited exactly since half past three

    I have waited since exactly half past three
is allowable because we are modifying a defined point in time as we did above, not the adjunct itself.
Sequencers are sometimes modified but the range of modifiers is severely limited:
    He had lunch just before two
    They spoke immediately afterwards

are fine but
    *He had lunch exactly before two
    *He came from London very originally
    *Immediately next, we went out

are not acceptable.

Modification of time adjuncts, as we would expect, works differently across languages and these kinds of restrictions will cause errors such as:
    *They immediately then opened the box
    *They very seldom but often enough work late
    *She came precisely recently


In the classroom

A sure way to encourage error in this area is to teach unprepared.  Unless you are very talented, it is unlikely that you will remember all the considerations which have been covered in this guide concerning adjunct form, position and function.
This is a complex area in which languages differ markedly in what adjuncts are possible, how they are used and what their functions are.
Relational vs. absolute time distinctions are particularly troublesome for learners from many language backgrounds because their languages may not make the distinction at all.
Equally troublesome for some learners is the fact that English deals with absolute time and duration rather differently.

  1. Distinguish between adverb time references and prepositional-phrase adjuncts.
    If you don't, learners will be encouraged to insert prepositional phrases in the medial position in clauses (which is rarely possible) or to place adverbs unnaturally at the ends of clauses so we will hear or read:
    1.     He came at 6 o'clock to the house
      which emphasises the time adjunct unnecessarily
    2.     He played tennis with his brother generally
      which focuses on his opponent not on the verb, and so on.
    3. and plain errors such as:
          *They'll have by six got here
          *I monthly visit my sister
          *They three times did it

      will also occur.
  2. Get the categories straight and present them or deal with them as discrete areas before mixing them.
    If you don't, bewildered learners may produce:
    1.     They went already
          They have started at six o'clock

      failing to distinguish between absolute and relative time.
    2.     *They again and again did it
          *They annually meet
          *They arrive often late
      failing to distinguish between definite and indefinite frequency, the former taking end position and the latter often taking medial position.
    3.     Tomorrow I will come to your party
      unnaturally stressing the adjunct and, perhaps, failing to distinguish between absolute time and sequencing.
    4.     ?Permanently, he was complaining
      failing to distinguish between duration and absolute time.
  3. Handle time and place adjuncts separately.
    If you have followed the guide to place adjuncts, linked in the list of related guides at the end, you will know that they operate quite differently from time adjuncts in English.  If you mix them up, you may get errors such as:
    1.     *They went dead at six
          *He finished clear before 7

      where the modifiers are not appropriate for time adjuncts.
    2. or
          *At six o'clock came Mary
      where there is confusion because an initial place adjunct often requires the subject–verb inversion as in, e.g.:
          *Here comes Mary
      but a time adjunct does not so it should be:
          At six o'clock, Mary came

Simply listening to your learners or reading carefully what they write may alert you to the areas which are causing trouble and then, using this guide, you should be able to plan and conduct a lesson or series of lessons which focuses on the trouble without introducing more confusion.

Related guides
prepositions of time for a guide to this set of prepositions
prepositions of place for a guide to this set of prepositions
place adjuncts for a parallel guide to these
prepositional phrases for a guide to prepositions and their complements
tenses in dependent clauses for a guide to how English deals with subordinate time clauses
assertion and non-assertion look here if the terms are unfamiliar and you want to know more
adverbials for a guide to distinguishing adjuncts from disjuncts from conjuncts
adverbs for a general guide to adverbs 

Chalker, S, 1984, Current English Grammar, London: Macmillan
Lock, G, 1996, Functional English Grammar, Cambridge: Cambridge University Press
Quirk, R, Greenbaum, S, Leech, G & Svartvik, J, 1972, A Grammar of Contemporary English, Harlow: Longman