1. It is necessary to have a day to celebrate our parents.
2. How long have you made acquaintance with her?
3. I had to stay up late last night to learn lessons.
4. Minh used to live in a farm when he was a small boy.
5. He asked me what I would do the next day.
6. I used to swim in this river but I don't do it anymore.
7. It's not easy to learn English at home.
8. What was the man wearing when you saw him?
9. I taught Mary to drive last year.
10. I have a lot of news to give you.
11. Teacher told us not to talk in the class.