Here are some general rules to help you decide what verb tense to use in an adverbial clause beginning with after, as, as soon as, before, until, when, or while. To talk about the present or past, use the same tense you would use in a main clause:
• I normally look after the children while she is practicing.
• When she heard the results, she was overjoyed.
To talk about the future, use a present tense:
• Wait here until you're ready to go.
• I'll look after the children while you are making dinner.
To talk about an action that is completed before another action described in the main clause, use either simple or perfect tenses:
As soon as you see / have seen her, come and tell me.
• She wrote to me after she spoke / had spoken to Jim.
However, if we are talking about an action in the adverbial clause that takes place over a period of time, we generally prefer the present perfect:
• After I have written this book, I'm having a holiday, (rather than After I write...)
• You can go when you've typed these letters, (rather than ...when you type...)
If the two actions take place at the same time, use a simple tense, not a perfect tense:
• Turn the light out as you leave, (not ...as you have left.)
• When I saw Kim, I asked her over for dinner, (not When I had seen...)
We use before if the action or event in the main clause has little or no duration and does not take place until the time represented in the adverbial clause:
• She walked out before I had a chance to explain.
We can often use either until or before when a situation described in the main clause lasts until a time indicated in the adverbial clause. In particular: • to say how far away a future event is:
• if the main clause is negative:
• It was three days until/before the letter arrived.
• I didn't think I'd like skiing until/before I tried it.
Compare the use of until and before when the main clause is positive:
• He used to live with us until/before he moved down to London.
Here, until means 'up to the time'. Before means 'at some time before (but not necessarily right up to the time specified)'. If the adverbial clause also describes the result of an action in the main clause, we use until: • He cleaned his shoes until they shone, ('shining' is the result of 'cleaning') When we say that one event happened immediately after another we can use sentences with hardly, no sooner, and scarcely:
• The concert had hardly begun before all the lights went out.
• I had no sooner lit the barbecue than it started to rain.
We often use a past perfect in the clause with hardly, no sooner or scarcely and a simple past in the second clause. After hardly and scarcely the second clause begins with when or before; after no sooner it begins with than. In a literary style, we often use the word order hardly / no sooner / scarcely + verb + subject at the beginning of the first clause
• Scarcely had Mrs James stepped into the classroom when the boys began fighting.
We can use as, when or while to mean 'during the time that...', to talk about something that is or was happening when something else took place:
• As/When/While Dave was eating, the doorbell rang, or • The doorbell rang, as/when/while Dave was eating.
The word whilst can also be used in this way, but is today considered rather literary. We use when (not as or while): • to talk about an event that takes place at the same time as some longer action or event (described in the main clause):
• They were playing in the garden when they heard a scream.
• Dave was eating when the doorbell rang,
• to talk about one event happening immediately after another:
• When the lights went out, I lit some candles.
• I knew there had been an accident when the police arrived.
• to talk about periods of our lives or periods of time past:
• His mother called him Robbie when he was a baby.
• to mean 'every time':
• I still feel tired when I wake up in the morning.
• When I turn on the TV, smoke comes out the back.
We use either as or when (not while): • to talk about two short events that happen at the same moment, or if we want to emphasize that two events that in fact occur one after the other happen almost at exactly the same time, particularly if one causes the other:
• You'll see my house on the right as/when you cross the bridge.
• As/When the can is opened, the contents heat automatically.
• when we want to say that when one thing changes, another thing changes at the same time. However, we prefer as to express this meaning:
• As the cheese matures, its flavor improves, (rather than When the cheese matures...)
• Her eyesight worsened as she grew older, (rather than ...when she grew older.)
We prefer while or as (rather than when): • to talk about two longer actions that go on at the same time: »
• I went shopping while/as Linda cleaned the house.
We use while (or when) rather than as if 'as' could also mean 'because':
• While you were playing golf, I went to the cinema. ('As you were playing golf...' could mean 'Because you were playing golf...')
Particularly in formal speech and writing, we can often leave out subject + be in clauses with when and while if the main and subordinate clause refer to the same subject:
• The President was on holiday in Spain when told the news. (= when he was told)
• When in doubt about taking the medicine, consult your doctor. (= when you are in doubt)
• Mr Thomas found the coins while digging in his back garden. (= while he was digging)
• While on the boat, always wear a lifejacket. (= while you are on the boat)
We can begin a clause with these words to give a reason for a particular situation:
• As it was getting late, I decided I should go home.
• We must be near the beach, because I can hear the waves.
• Since he was going to be living in Sweden for some time, he thought he should read something about the country.
• It is also common and acceptable for because to begin a sentence, as in:
• Because everything looked different, I had no idea where to go. •
To give reasons in spoken English, we most often use because (often spoken as 'cos'). So is also commonly used to express the same meaning.
Compare: • Because my mother's arrived, I won't be able to meet you on Thursday after all. • My mother's arrived, so I won't be able to meet you on Thursday after all.
• With this meaning, since is rather formal: • I didn't go out because I was feeling awful, ('since' is unlikely in an informal context)
• Seeing that is used in informal English. Some people also use seeing as in informal speech:
• He just had to apologize, seeing that/as he knew he'd made a mistake.
We also give reasons with these phrases in formal or literary written English:
• We must begin planning now, for the future may bring unexpected changes.
• The film is unusual in that there are only four actors in it.
• Clara and I have quite an easy life, inasmuch as neither of us has to work too hard but we earn quite a lot of money.
Because of, due to, owing to can also be used to give a reason for something. Because of is used before a noun or noun phrase:
• We won't be able to come because of the weather.
• The Prime Minister returned home because of growing unrest in the country.
Compare: • We were delayed because there was an accident, (not ...because of there was...) and • We were delayed because of an accident, (not ...because an accident.)
Due to and owing to also mean 'because of:
• She was unable to run owing to/due to a leg injury. (= because of a leg injury.)
• We have less money to spend owing to/due to budget cuts. (= because of budget cuts.)
Most people avoid using owing to after the verb be:
• The company's success is largely due to the new director, (not ...owing to...)
We can use for and with to introduce reasons. For has a similar meaning to 'because of:
• She was looking all the better for (= because of) her stay in hospital.
With this meaning, for is common in most styles of English. With has a similar meaning to 'because there is/are': • With so many people ill (= because so many people are ill), I've decided to cancel the meeting. Notice we can use with, but not for, at the beginning of a sentence to introduce a reason.
To talk about the PURPOSE of something we can use in order / so as + to-infinitive:
• He took the course in order to get a better job.
• Trees are being planted by the roadside so as to reduce traffic noise.
In spoken English in particular it is much more common simply to use a to-infinitive without 'in order' or 'so as' to express the same meaning:
• He took the course to get a better job.
To make a negative sentence with in order / so as + to-infinitive, we put not before the to-infinitive:
• He kept the speech vague in order not to commit himself to one side or the other.
• The land was bought quickly so as not to delay the building work.
You can't use a negative if you use only a to-infinitive:
• I carried the knife carefully in order / so as not to cut myself, (not ...carefully not to cut...)
However, compare negative sentences with in order / so as / to-infinitive + but:
• I came to see you not (in order / so as) to complain, but (in order /so as) to apologize.
We also use in order that and so that to talk about PURPOSE. Compare:
• She stayed at work late in order / so as to complete the report, and • She stayed at work late in order that / so that she could complete the report.
So that is more common than in order that, and is used in less formal situations. Study these examples. Notice in particular the verbs and tenses:
• Advice is given in order that / so that students can choose the best courses.
• Did you give up your job in order that / so that you could take care of your mother?
• She bid the present in order that / so that the children wouldn't find it.
Study these examples with for or to-infinitive used to talk about PURPOSE: To talk about the purpose of an action: for + noun or to-infinitive
To talk about the purpose of a thing, or to define it: for + -ing
To talk about the use a person makes of something: to-infinitive
We use so...that to link a CAUSE with a RESULT. In speech, 'that' is often left out:
• The train was so slow (that) I was almost two hours late.
• It all happened so quickly (that) I never got a good look at his face.
For special emphasis, particularly in formal English, we can put So ... that at the beginning of a sentence and put the verb before the object:
• So slow was the train that I was almost two hours late.
• So quickly did it all happen that I never got a good look at his face.
We can sometimes use so...as + to-infinitive instead of so...that:
• It was so unusual as to seem almost a joke. (= ...so unusual that it seemed almost...)
• I'm saving for a new car.
• I'm saving to buy a new car.
• This is good for getting rid of headaches.
• A mouse is a device used for moving the cursor around a computer screen.
• She used a heavy book to keep the door open.
We use although or though when we want to say that there is an unexpected contrast between what happened in the main clause and what happened in the adverbial clause:
• Although/Though Reid failed to score himself, he helped Jones score two goals, (or Reid failed to score himself, but he helped Jones score two goals.)
• She bought a car, although/though she was still too young to learn to drive, (or She was still too young to learn to drive, but she bought a car.)
We can usually use either although or though, but though is often less formal. Though, but not although, can also be used as an adverb to say that the information in a clause contrasts with information in a previous sentence:
• I eat most dairy products. I'm not keen on yoghurt, though, (not ...although.)
• 'That cheese smells awful!' 'It tastes good, though, doesn't it?' (not ...although...)
We can give special emphasis to an adjective or adverb by putting it before though or as, especially when followed by a linking verb such as be, appear, become, look, seem, sound, prove, etc. Notice that in this pattern you can't use although.
Compare: • Although/Though the night air was hot, they slept soundly, and • Hot though (or as) the night air was, they slept soundly, (not Hot although the night air...)
• Although/Though it may seem extraordinary, London had less rain than Rome, and • Extraordinary though (or as) it may seem, London had less rain than Rome, (not Extraordinary although it may seem...)
Much as is used in a similar way before a clause, particularly to talk about how we feel about someone or something:
• Much as I enjoyed the holiday, I was glad to be home. (= Although I enjoyed...)
We can use even though (but not 'even although') to mean 'despite the fact that' and even if to mean 'whether or not'.
Compare: • Even though Tom doesn't speak Spanish, I think he should still visit Madrid. • Even if Tom doesn't speak Spanish, I think he should still visit Madrid.
We can use in spite of + -ing with a similar meaning to 'although':
• In spite of playing with ten men, we won easily. (= Although we played with ten men...)
• In spite of being full of water, the boat sailed on. (= Although the boat was full...)
In spite of can also be followed by a noun:
• In spite of their poverty, the children seemed happy. (= Although they were poor...)
Notice that despite is often used instead of in spite of, particularly in written English:
• Despite falling / In spite of falling midway through the race, she won.
Despite and in spite of are never followed by a clause with a finite verb. So, for example, you can't say 'Despite / In spite of she fell midway through the race...'. However, you can use a clause with a finite verb after the fact that:
• Despite / In spite of the fact that she fell midway through the race, she won.