=>
2/
1. be
2. working
3. work
4. speaking
5. wearing
6. living
7. commute
8. read
9. wearing
10. bite

13/
3. Peter used to play the guitar two years ago. Now he plays the violin.
4. He used to go to the cinema regualrly, but now he doesn't. 
5. I used to eat sweets when I was a boy.
6. Sarah used to bite her nails when she was a child.
7. We used to get into the hait of swimming every day before breakfast.
8. There used to be some trees here, but now there aren't any.
9. She used to get up early and have a bath every morning.

EX 12.
      1. be.                                    2. working.
      3. work.                               4. speaking.
        5. wearing.                         6. living.
       7. commute.                       8. read.
       9. wearing.                        10. bite.

EX 13.

Câu 1 và câu 2 bạn làm đúng rồi.

      3. Peter used to play the guitar two years ago. Now he plays the violin.
      4. He used to go to the cinema regualrly, but now he doesn't. 
       5. I used to eat sweets when I was a boy.
      6. Sarah used to bite her nails when she was a child.
      7. We used to get into the hait of swimming every day before breakfast.
     8. There used to be some trees here, but now there aren't any.
      9. She used to get up early and have a bath every morning.