1. If it (rains) tomorrow, we (will stay) at home.
2. If you (study) hard, you (will pass) the exam.
3. If she (invites) me, I (will go) to her party.
4. If we (don't hurry), we (will miss) the bus.
5. If you (don't water) the plants, they (will die).
6. If I (see) her, I (will tell) her the news.
7. If he (is) late, we (will start) without him.
8. If you (eat) too much, you (will feel) sick.
9. If they (don't come) soon, we (will leave).
10. If you (drop) that glass, it (will break).
11. If we (finish) early, we (will go) to the cinema.
12. If she (asks) politely, he (will help) her.
13. If you (touch) that wire, you (will get) a shock.
14. If he (doesn't listen) carefully, he (will fail) the test.
15. If they (need) a ticket, I (will buy) one for them.
16. If you (help) me, I (will finish) this project faster.
17. If my brother (has) enough money, he (will buy) a car.
18. If we (don't leave) now, we (will be) late.
19. If the weather (is) nice, we (will go) for a walk.
20. If she (practices) every day, she (will become) a good singer.
21. If he (wins) the lottery, he (will travel) around the world.
22. If you (phone) me tonight, I (will tell) you the result.
23. If they (work) hard, they (will complete) the project on time.
24. If she (doesn't feel) well, she (will stay) at home.
25. If you (break) the rules, you (will be) punished.
26. If it (snows) this evening, we (will make) a snowman.
27. If I (find) your key, I (will give) it to you.
28. If he (drives) carefully, he (will avoid) accidents.
29. If she (cooks) dinner, we (will clean) the dishes.
30. If you (send) me your address, I (will post) the letter.
Here are the answers to the exercise:
1. have
2. studies
3. is
4. can get
5. ask
6. doesn't come
7. don't leave
8. saves
9. practise
10. studies
11. rains
12. eat
13. don't hurry
14. helps
15. go
16. touch
17. doesn't wear
18. find
19. practise