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1. If you don't keep silent, you will wake the baby up.
2. If I knew the answer, I could tell you.
3. If we had had the map, we wouldn't have got lost.
4. If my friend hadn't been so late, he wouldn't have missed the train.
5. If we lived without the air, we would die
6. If you don't be calm, you'll make a wrong decision.
7. If he hadn't had a visa, he couldn't have come to that country.
8. If today was Sunday, the students would go swimming.
9. If I knew her number, I would ring her up.
10. If I had known Alice's address, I would have written to her.
Câu ĐK loại 1( có thể xảy ra ở hiện tại hoặc tương lai) If + S + V(s,es), S + will/can/shall... + V
Câu ĐK loại 2( không có thật ở hiện tại) If + S + V2/Ved, S + would/could/should... + V
Câu ĐK loại 3( không có thật ở quá khứ) If + S + had + V3, S + would/could... + have + V2/Ved
