Conditional clauses

8.25 When you want to talk about a possible situation and its consequences, you use a conditional clause.

Conditional clauses are used:

• to talk about a situation which sometimes exists or existed

If they lose weight during an illness, they soon regain it afterwards.

Government cannot operate effectively unless it is free from such interference.

If I saw him in the street, he'd just say 'Good morning'.

• to talk about a situation which you know does not exist

If England had a hot climate, the attitude would be different.

If I could afford it I would buy a boat.

• to talk about a situation when you do not know whether it exists or not

If he is right it would be possible once more to manage the economy in the old way.

There's no reason why she should have come here unless it was to cadge free drinks.

• to talk about a situation which may exist in the future.

If I marry Celia we shall need the money to live on.

If I went pack on the train it'd be cheaper.

Don't bring her unless she's sober.

Sentences containing conditional clauses are sometimes called conditional sentences.

8.26 Conditional clauses usually begin with 'if' or 'unless'.

You use 'if' to say that a consequence of something happening or being the case would be that something else would happen or be the case.

If you do that I shall be very pleased.

If I asked for something I got it.

They will even clean your car if they're in the mood.

When an 'if'-clause is put first, 'then' is sometimes put at the beginning of the main clause.

If this is what was happening in the Sixties, then I'm glad I wasn't around then.

'Unless' means 'if...not'. For example, 'You will fail your exams unless you work harder' means 'If you do not work harder, you will fail your exams'.

There can be no new growth unless the ground is cleared.

Nobody gets anything unless they ask for it.

Clauses beginning with 'unless' usually go after a main clause.

modals and imperatives 8.27 When you are using a conditional clause, you often use a modal in the main clause.

You always use a modal in the main clause when you are talking about a situation which does not exist.

If you weren't here, she would get rid of the in no time.

If anybody had asked me, I could have told them what happened.

Modals are explained in paragraphs 4.95 to 4.262.

Conditional clauses are often used with imperative structures.

If you dry your washing outdoors, wipe the line first.

If it's four o'clock in the morning, don't expect to them to be pleased to see you.

Imperative structures are explained in paragraphs 4.4 and 4.31 to 4.35.

8.28 There are special rules about which tense to use in conditional sentences.

Foreign learners are often taught that there are three kinds of conditional sentence:

• the first conditional, in which the verb in the main clause is 'will' or 'shall' and the verb in the conditional clause is in the simple present tense

• the second conditional, in which the verb in the main clause is 'would' or 'should' and the verb in the conditional clause is in the simple past tense

• the third conditional in which the verb in the main clause is 'would have' or 'should have' and the verb in the conditional clause is in the past perfect tense.

This is largely correct, but does not fully describe the normal patterns of tense in conditional clauses which are set out in the following paragraphs.

8.29 When you are talking about a common occurrence, you use the simple present tense or the present continuous tense in the conditional clause and in the main clause.

If a man looks at me, I am flattered.

He never says a word unless he feels he's being threatened in some way.

If a tap is dripping, it needs a new washer.

If an advertisement conveys information which is false of misleading, the advertiser is committing an offence.

8.30 When you are talking about a common occurrence in the past, you use the simple past tense or the past continuous tense in the conditional clause. In the main clause, you use the simple past tense or a modal.

They sat on the grass if it was fine.

If it was raining, we usually stayed indoors.

If anyone came, they'd say 'How are you?'

If they wanted to go out, they could always count on the to stay with the baby.

Often I could not fall asleep unless I exercised to the point of exhaustion.

8.31 When you are talking about a possible situation in the present, you usually use the simple present tense or the present perfect tense in the conditional clause. In the main clause you usually use a modal.

If anyone doubts the truth of this, they should look at the two most successful post-war economies, Germany and Japan.

Unless you've tried it, you can't imagine how pleasant it is.

'If'-clauses of this kind can be used when you are offering to do something, or giving permission for something to be done. You use a modal in the main clause, and the subordinate clause consists of 'if', a pronoun, and 'want', 'like', or 'wish'.

I'll teach you, if you want.

You can leave if you like.

8.32 When you are talking about a possible future occurrence, you use the simple present tense in the conditional clause, and the simple future tense in the main clause.

If I ever get out of this alive, I'll never leave you again.

If nuclear weapons are employed in a world war, the world will be destroyed.

Willie will be a failure in life unless he is pushed.

USAGE NOTE 8.33 A more formal way of taking about a possible future situation is to use 'should' in the conditional clause. For example, instead of saying 'if anything happens, I will return immediately', you can say 'If anything should happen, I will return immediately'. In the main clause you use a modal, usually 'will' or 'would'.

If anyone should come this way, we would be caught like rats in a trap.

Another way of talking about a possible future situation is to use 'were' and a 'to'-infinitive in a conditional clause. For example, instead of saying 'If he goes, I will go too', you can say 'If he were to go, I would go too'. In the main clause you use 'would', 'should', or 'might'.

If we were to move north, we would be able to buy a bigger house.

unlikely situations 8.34 When you are talking about an unlikely situation, you use the simple past tense in the conditional clause, and 'would', 'should', or 'might' in the main clause.

The older men would find it difficult to get a job if they left the farm.

I should be surprised if it was less than five pounds.

If I frightened them, they might take off and I would never see them again.

In the conditional clause, 'were' is sometimes used instead of 'was', especial after 'I'.

If I were as big as you, I would kill you.

If I were asked to define my condition, I'd say 'bored'.

what might have been 8.35 When you are talking about something that might have happened in the past but did not happen, you use the past perfect tense in the conditional clause. In the main clause, you use 'would have', 'could have', 'should have', or 'might have'.

Perhaps if he had realized that, he would have run away while there was still time.

If she had not married, she would probably have become something special in her field.

putting the verb first 8.36 In formal or literary, English, if the first verb in an 'if'-clause is 'should', 'were', or 'had', this verb is sometimes put at the beginning of the clause and 'if' is omitted. For example, instead of saying 'It any visitors should come, I will say you are not here', someone might say 'Should any visitors come. I will say you are not here'.

Should ministers decide to instigate an inquiry, we would welcome it.

Were it all true, it would still not excuse their actions.

Were they to cease advertising, prices would be significantly reduced.

Had I known that there was never to be another opportunity, I would have filmed the occasion.

USACE NOTE 8.37 Instead of using a conditional clause containing the word 'be', you can sometimes use a phrase consisting of 'if' followed by an adjective or a prepositional phrase. For example, instead of saying 'We will sell the car, if it is necessary', you can say 'We will sell the car, if necessary'.

This unfortunate situation is to be avoided if possible.

If I were innocent, I'd rather be tried here; if guilty, in America.

If in doubt, ask at your local library.

8.38 If you want to say that one situation is necessary for another, you use 'provided', 'providing', 'as long as', 'so long as', or 'only if'. 'Provided' and 'providing' are often followed by 'that'.

A child will learn what is right and what is wrong in good time-provided he is not pressured.

Lady Sackville was prepared to come, provided that she might bring her daughter.

The oven bakes magnificent bread providing there is a hot enough fire in the furnace.

They are content for the world to stay as it is, poverty, pain and everything, as long as they are comfortable.

These activities can flourish only if agriculture and rural industry are flourishing.

When you are using 'only if', you can put the 'only' in the main clause, separated from the 'if'. For example, instead of saying 'I will come only if he wants me', you can say 'I will only come if he wants me'.

He told them that disarmament was only possible if Britain changed her foreign policy.

Another way of saying that one situation is necessary for another is to use a conditional clause consisting of 'if' followed by the subject, a form of 'be', and a 'to'-infinitive clause. In the main clause, you say what is necessary using 'must'.

It's late, and if I am to get any sleep I must go.

If you are to escape, you must leave the and go on alone.

8.39 If you want to say that one situation would not affect another, you can use 'even if'.

I would have married her even if she had been penniless.

Even if you've never been taught to mend a fuse, you don't have to sit in the dark.

Even if we do not resort to such dramatic measures, it seems likely that there will be many exciting opportunities in the future.

'Even if' is also used in concessive clauses. This is explained in paragraph 8.67.

5.40 If you want to say that a situation would not be affected by any of two or more things, you use 'whether'. You put 'or' between the different possibilities.

If the lawyer made a long, oratorical speech, the client was happy whether he won or lost.

Catching a frog can be a difficult business, whether you're a human or a bird or a reptile.

Whether you go to a launderette or do your washing at home, the routine is the same.

If you want to say that what happens would not be affected by either of two opposite situations, you use a clause beginning with 'whether or not'.

Whether or not people have religious faith, they can believe in the power of love.

I get an electrician to check all my electrical appliances every autumn, whether or not they are giving trouble.

'Or not' can be put at the end of the clause.

Whether I agree or not, the search would take place.

USAGE NOTE 8.41 When the verb in a 'whether'-clause is 'be', the subjunctive mood is sometimes used. When you use the subjunctive mood, you use the base form of a verb rather than the third person singular. This is rather formal.

Always immediately report such behaviour to the nearest person in authority, whether it be a school teacher or a policeman or anyone else.

When the verb in a 'whether'-clause is 'be' and the subject is a personal pronoun such as 'they' or 'it', you can omit 'be' and the pronoun. For example, instead of saying 'All the villagers, whether they are young or old, help with the harvest', you can say 'All the villagers, whether young or old, help with the harvest'.

A fresh pepper, whether red or green, lasts about three weeks.

They help people, whether chance visitors or students of medieval history, to learn more or our past.

8.42 When you want to say that something is the case and that it does not matter which person, place, cause, method, or thing is involved, you use 'whoever', 'wherever', 'however', 'whatever', or 'whichever'.

Whoever wins this civil war there will be little rejoicing at the victory.

Wherever it is, you aren't going.

However it began, the battle was bound to develop into a large-scale conflict.

'Whatever' and 'whichever' are used either as determiners or pronouns.

Whatever brand you use, you will need four times as many teaspoonfuls as before.

That is why the deficit remains of key importance this year, whatever the Chancellor might say.

Whichever way you look at it, neutrality is folly.

You can either sow wheat in rows or broadcast it. Whichever you do, it is a good thing to break up the soil after seeding.

Another way of saying that it does not matter who or what is involved is to use 'no matter' followed by 'who', 'where', 'how', 'what', or 'which'.

Most people, no matter who they are, seem to have at least one.

Our aim is to recruit the best person for the job, no matter where they are from.

No matter how I'm playing, I always get that special feeling.