1. Heavy rain prevented everyone from going out.

2. He is not good enough to start a conversation in English.

3. I didn't send you an email because you didn't inform me that you were online.

4. The church bells prevent me from sleeping.

5. Maintaining a healthy weight is helped by eating lots of vegetables and fruit.

6. If you leave now, I will never speak to you again.

7. Because the boy is so young, he can't attend school.

8. The machine stops working when you press that button.

9. Why don't you invite him to your birthday party?

10. The wind was so strong that we couldn't go sailing.

11. If you keep following me, I'll call the police.

12. Remain calm, or you'll make a wrong decision.

13. She hid behind her mother due to her shyness.

14. She couldn't have entered that country without a visa.

15. Tom's big house allowed us to stay there.

16. Working in the garden leaves him feeling very tired.

17. His confidence was enough for him to perform on stage.

18. Her many friends ensure that she never gets bored.

19. Because I was busy, I didn’t watch TV last night.

11. If it hadn't rained heavily, everybody would have gone out.

12. If he were good enough, he would start a conversation in English.

13. If you had told me you were online, I would have sent you an email.

14. If the church bells didn't ring, I would sleep.

15. If you eat lots of vegetables and fruit, you will maintain a healthy weight.

16. If you leave now, I will never speak to you again.

17. If the boy were older, he could go to school.

18. If you press that button, the machine will stop working.

19. Why don't you invite him to your birthday party? (This sentence already expresses a condition.)

20. If it hadn't been so windy, we could have gone sailing.

21. If you stop following me, I won't call the police.

22. If you stay calm, you won't make a wrong decision.

23. If she weren't so shy, she wouldn't hide behind her mother.

24. If she had had a visa, she could have come to that country.

25. If there were no plants, animals wouldn't have any oxygen to breathe.

26. If Tom didn't have a big house, we couldn't stay at his house.

27. If he didn't work in the garden, he wouldn't be so tired.

28. If he weren't confident, he couldn't perform on stage.

29. If she didn't have many friends, she would get bored.

30. If I hadn't been busy, I would have watched TV last night.