1.They don't go with us because they have a lot of homework

2.Because it was cold , I turned the heating on

3. cho vào giữa nhé

4. Although it rained a lot , we enjoyed our holiday

5.Although he often tells lies , many people believe him.

6. Although she was too tired , she tried her best to finish her work

7.If she drinks a lot of milk ,she is heathy
8. You aren't late for the meeting if you get up early

9.If we use less paper , we save a lot of trees

10. eat ---> eaten

11.didn't come

12. has been

13.seen

14.When did Lan talk to Minh about his trip ?

15.Why does your sister hate this kind of film?

16.Why did you call the doctor yesterday ?

17.I will live in a vila on the sea in the future