1. If he had been able to afford it, he her a diamond ring. (BUY)

2. If it rains this afternoon, we out. (NOT GO)

3. If she the exam, she won't get the job she has applied for. (NOT PASS)

4. If she posted the letter now, they   it by Tuesday. (RECEIVE)

5. If I about the dinner I would have come earlier. (KNOW)

6. My boss angry if John comes to work late again. (BE)

7. If my girlfriend left me, I miserable. (FEEL)

8. I that if I were you. (NOT SAY)

9. If I had lost my way I to the nearest police station. (GO)

10. If I a spider in my bathroom I would cry out loud. (SEE)

11. The teacher will be very angry if you in your homework on time. (NOT HAND)

12. If you to learn a lot, you would have taken this course. (WANT)

13. If you   quickly you will catch the bus. (RUN) 

14. I would be very proud if she my sister. (BE)

15. I to your party if I had had time. (COME)

16. If you 16. If you   the flowers, they won't survive. (NOT WATER)the flowers, they won't survive. (NOT WATER)

17. The beach would be an ideal place for a picnic if it so crowded. (NOT BE)

18. If she the book carefully, she would have understood it. (READ)

19. Be careful! If you touch this wire you   a shock. (GET)

20. She could win the race if she . (TRY)