Section 2 - Likely conditionals in the past, present and future

IDevice Icon Verb forms in the if-clause
Present or future

To talk about conditions in the present or future that we think are likely to happen, we use Present tenses or modals. This is the most common form of conditional sentence:

If he comes into the room, don't mention the party this evening.
'Can I leave early today?' 'If you must.'
  • To talk about the future, we can also use going to in the if-clause.
Even if we're not going to go swimming, we'd still better take a towel.

  • Can for ability is also common in if-clauses:
Assuming you can leave work early, we'll be able to make the 6.30 performance.


Past

To talk about events in the past, we can use Present Perfect or Past Simple / Continuous. This suggests that either we are not sure if something happened, or we are assuming it did and want to draw a conclusion from it (see Overview for false conditionals, and see Section 4 for unlikely conditionals in the past):

If he's read that report, he'll know what all the fuss is about.
If you've been telling the truth, we need to act quickly.
Provided that she caught her flight, she'll be landing any moment now.

IDevice Icon Will / won't in the if-clause

We sometimes use will and won't in the if-clause with the meanings of refusal (won't), polite request (will), or strong disapproval at someone's insistence on doing something (will):

If he won't go, there is nothing you can do about it. (= refusal)
If you'll hold this end, I'll take the other one. (= request)
If you will drive so fast, you must expect to have accidents. (= insistence)

 

Watch out!

Apart from the meanings above, we don't normally use will in if-clauses to indicate the future:

If the weather will be fine tomorrow, we can go for a walk. - INCORRECT
If the weather is fine tomorrow, we can go for a walk. - CORRECT

 


IDevice Icon Verb forms in the main clause

Verb forms in the main clause follow the normal rules for tense and modal use. Some of the most common are:

Present Simple
 		to indicate certainty of the result:
If you mix blue and red, you get purple.
will
to predict future events, make promises, etc:
Provided I see him, I'll tell him.
will have
to predict what will have happened:
The train will have left if we don't get there soon.
can
to express ability, permission, etc:
You can do it that way if you like, but I wouldn't recommend it.
going to
for predictions or intentions:
If you do that again, I'm going to leave.



IDevice Icon Mixing time references
It is sometimes possible to have an if-clause referring to the present or future, and a main clause referring to the past, especially with must have and can't have for deductions:

If he's here already, he must have set off very early.

IDevice Icon False conditionals
False conditionals (see Overview) are very common when mixing time references:

'I don't eat red meat.' 'Well, if that's a problem we'll have to find another restaurant.'

iDevice icon Check!
Which sentences are incorrect?
a. We'd better get ready if he's coming round soon.
b. If I have to, I'm going to tell him what I think of him.
c. If the film will be uninteresting, we can leave before the end.
d. If you don't understand, why didn't you ask me?
e. If you'll just wait a moment, I'll see if he's in.

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