1. If he (pass) his examination, we’ll have a celebration.
2. What (happen) if I press this button?
3. If it (not rain) now, we would go to the country.
4. If we had booked tickets beforehand, we (not have) to wait now.
5. If I (be) you, I would ring him up myself.
6. If you don’t give me more information, I (not be) able to help you.
7. If it (not be) so cold yesterday, we would have gone to the forest.
8. If he were careful, he (not break) things.
9. If you (not help) me, I wouldn’t have been able to finish the work yesterday.
10. We won’t go to the theatre if he (not bring) tickets.
11. If he (not be) at home, leave him a note.
12. If you had learnt the words, you (not do) so many mistakes.
13. If Ann were slimmer, she (be) much more attractive.
14. If I (have) a chance last year, I would have visited Great Britain.
15. I will let you know if he (come).
16. If you (not hurry), you’ll miss the train.
17. I would buy this book if it (not be) so expensive.
18. ‘Does she love him?’ ‘Of course she does. If she (not love) him, she (not marry) him.’
19. ‘What you (do) if you saw a ghost?’ ‘I (run) a mile.’
20. If I (not be) busy, I’ll visit you.

1) pass 2) happen 3) is not raining 4) don't have 5) will be you 6) wouldn't 7) wasn't 8) won't break

1passes2will happen3rained4wouldn't have had5were6won't be able7were not8wouldn't break9had helped10doesn't bring11isn't12wouldn't have done13would be14had had15comes16don't hurry17wasn't18doesn't love.won't marry19what would you do....I would run a mile.20I'm not busy