The main linking words for conditional clauses are if and unless, but even if, as/so long as, supposing, whether...or, however(+ adjective/determiner), whoever, wherever, whenever, etc., providing/provided(that), no matter who/how/when etc. can also be used:
If they are short of money, they don't eat out. (Zero Conditional)
You'll have a tussle with the management if you go ahead with that plan. (First Conditional, possible future action)
If they had a bigger garden, they would grow their own vegetables. (Second Conditional, hypothetical but possible) Similarly: If you were to join the committee, we'd be very pleased.
Note that Were you to join is more formal.
If you hadn't been late, you would have understood the lecture. (Third Conditional, referring to a past situation) Note that Had you arrived on time...is a more formal version.
If you hadn't been late, you'd know what we are talking about now. (Mixed Conditional)
Exercise 1. Complete the sentences with the correct tense of the verb in brackets.
If you (make) a run for it, you'll catch the train.
If Laura (not eat) so much, she wouldn't have put on weight.
If they (have) their car serviced regularly, it never lets them down.
The earthquake would have caused less damage if the houses (be) of stronger construction.
If there (be) a good breeze on Sunday, we'll go hang-gliding.
You can get there more quickly if you (take) the short cut across the railway bridge.
If you (leave) the milk out of the fridge in this weather, it'll go off.
Would you contribute to the fund if I (ask) you?
If I (drop) Eve's vase, she'd have been furious.
If you (be) really my friend, you'd lend me some money.
11. Had the councilors been re-elected, your proposal (be) accepted.
12. Productivity will improve if manufacturing procedures (be) streamlined.
(be) you to take out the relevant insurance policy, you would be completely covered.
No matter what (happen), I'll always stand by him.
Supposing the computer (break down), what would you do?
You can invite whoever you (like) to the barbecue.
I wish/If only + Past Simple are used to express a wish or regret about a current situation, by imagining its opposite: I wish/If only Mark knew about it. (Sadly, Mark doesn't know about it.)
Notice also: I would rather Mark knew about it. (a preference rather than a wish)
It's time Mark knew about it. (In my opinion he should)
I wish/If only + would are used for a future wish - something we would like to happen:
If only Mark would come back! (I'm afraid he won't.)
I wish you'd stop doing that. (You are annoying me.)
I wish/If only + Past Perfect are used for a past wish or regret:
I wish someone had told Mark about it.
Note that we use could instead of would with wish when the subject pronouns are the same: I wish I could see him. (NOT I wish I would see him.)
Were is often used instead of was after wish and if only: I wish Luke were here.
As if/as though are often used in similar hypothetical situations:
Don't treat me as if I were a child. He spoke as though he had been insulted.
Exercise 2. Match the correct wish or regret on the left with the situation on the right.
1. If only he would tell her! A It's a pity he didn't tell her.
2. I wish he had stayed. B We have no idea what to do.
3. If only we knew what to do! C We didn't know what to do.
4. I wish he had told her. D I'd like him to tell her.
5. I wish we'd known what to do. E It's a pity he didn't stay.
6. It's time he stopped smoking. F I'd like him to stay, if possible.
7. I'd rather he stayed. G I think he should stop smoking.
8. If only he'd stopped smoking! H He should have stopped smoking.
Exercise 3. Make a new sentence for each situation, starting with' I wish'.
What a pity he's so boring!
It was a mistake of mine, accepting that job.
How unfortunate that they all heard about it!
It'd be useful to have shares in the company, but I haven't any.
Is it ever going to stop snowing?
I should have gone to the conference.
I simply can't remember Myra's address.
I'd like him to contribute his opinions more tactfully.