Page 267 - Practical English Usage 3ed - Michael Swan, Oxford

2
if + past; would + infinitive without to
To talk about unreal or improbable situations now or in the future, we use a past tense in the if-clause (even though the meaning is present or future), and would + infinitive (without to) in the other part of the sentence.
IfI knew her name, I would tell you. (NOT If: 1en6W •••) (NOTIf:WfJttitJ1en6W•••) (NOT •••lwiHtellytltt.)
She would be perfectly happy ifshe had a car.
What would you do if you lost your job?
This structure can make suggestions sound less definite, and so more polite.
It would be nice ifyou helped me a bit with the housework. Would it be all right if I came round about seven tomorrow?
would, should and'd
After I and we, should can be used with the same meaning as would. (Would is more common in modem English; should is rare in ArnE.)
If I knew her name, I should tell you.
If I married you, we should both be unhappy.
We use 'd as a contraction (see 143).
We'd get up earlier if there was a good reason to.
For 1should . .. meaning " advise you to .. .', see 264.2. For lVould in the if-c1ause, see 262.
For should in the if-clause, see 261.1.
ifIwereetc
We often use were instead of was after if. This is common in both formal and informal styles. In a formal style were is more common than was, and many people consider it more correct, especially in American English. The grammatical name for this use of were is 'subjunctive' (see 567).
If1 were rich, I would spend all my time travelling. If my nose were a little shorter I'd be quite pretty.
For the expression If1were you ..., see 264.
ordinary tense-use or special tense-use? If I come or if I came?
The difference between, for example, ifI come and ifI came is not necessarily a difference of time. They can both refer to the future; but the past tense suggests that a future situation is impossible, imaginary or less probable. Compare:
3
4
5
6
- If I become President, I'll ... (said by a candidate in an election) IfI became President, I'd ... (said by a schoolboy)
- IfI win this race, I'll ... (said by the fastest runner) IfI won this race, I'd ... (said by the slowest runner) - Will it be all right if I bring a friend? (direct request)
Would it be all right ifI brought a friend? (less direct, more polite) could and might
We can use could to mean 'would be able to' and might to mean 'would perhaps' or 'would possibly'.
if (3): special structures with past tenses and would 258
page 235
~