12. If your english isn't good, they won't accept you.

13. If they open the door, the room won't be dark.

14. If you spend too much on shopping, you won't save a lot of money.

15. If we don't pollute the river, we will have water to use.

16. If I don't show you how to write a book, you will not try to study.

17. If she hurries, she won't be late for school.

18. If you take the medicine, your health won't be worse.

19.If you don't do this exercise well, I won't give you ten good marks

20.If she travels by plane, she will be on time for the meeting

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Câu điều kiện loại 1:

[If + thì hiện tại đơn], [will + động từ nguyên mẫu]