1. I think it is necessary to celebrate Mother's Day in Vietnam.

2. I suggest going on a picnic in the countryside.

3. If Mr. Hai had money, he would buy a car.

4. The teacher who taught us last year was Mrs. Greens.

5. If you don't study hard, you'll meet difficulties later.

6. She was surprised that he phoned her last night.

7. It'll be easier for us to learn new words with a good dictionary.

8. I haven't met my parents since last Sunday.

9. The picture which was painted by Picasso is very famous.

10. It is important for us to learn English well.

11. Giống câu 7

12. The man who used to be my French teacher moved to Paris last year.

13. She doesn't have a computer, so she hasn't finished her report yet.

14. Although it was rain last night, he went to the show on time.

15. He sorry that he broke my bicycle yesterday.