Dưới đây là các câu viết lại với nghĩa không đổi theo cấu trúc câu điều kiện "if":

1. If I had known that you were in the hospital, I would have visited you.
2. If you don’t hurry up, you will be late.
3. If she weren’t so busy, she could help me now.
4. If he had known my phone number, he would have called me.
5. If you took exercise, you wouldn’t be unfit.
6. If you are not careful, you will cut yourself with that knife.
7. If I have time, I will help you.
8. If Dick had studied his lessons carefully, he wouldn’t get bad marks now.
9. If Dick didn’t drive carelessly, he wouldn’t cause accidents.
10. If I knew English, I could apply for that job.
11. If Susan didn’t eat so much chocolate, she wouldn’t be overweight.
12. If he were lazy, his father would not often punish him.
13. If you don’t study harder, you will fail in the next exam.
14. If we had had time, we would have visited the museum.
15. If Jack hadn’t helped me, I wouldn’t have been able to move the table.