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1. Unless he works hard, he will not pass his exam.

2. If I had enough time, I could/would go on holiday this summer.

3. If I knew the answer, I would tell you.

4. If they don't review the lesson carefully, they won't do the test well.

5. If the people protect the environment now, the environment will be nicer.

6. If they had a map, they wouldn't get lost.

7. Unless you like this one, I'll bring you another.

8. Many houses in this village were destroyed by the storm last week.

9. If the festival costs too much money, we won't hold it.

Câu đk loại 1: If S Vs/es, S will (not) V

Câu đk loại 2: If S V2/ed, S would/could (not) V

Bị động QKĐ: S was/were V3/ed (by O)