1. C
2. D
3. A
4. B
5. D
6. B
7. D
8. B
9. C
10. C

Bài 1: 3/ He won't earn much if he does not work harder.
-> Unless he work harder, he won't earn much
4) I need fifteen minutes to get to the post office.
-> It took me fifteen minutes to get to the post office.
5) They use cars and trucks to carry food to market
-> Cars and trucks are used to carry food to market
6/ Unless you start working now, you won't be able to pass your exam
-> If you don't start working now, you won't be able to pass your exam
7/ My students are very good at Math
->  My students study Math very well
8/ It's 10 days since he came here
-> He hasn't left here for 10 days
9/ John's flat was broken into last week
10/ He has been known well by them