1.=> He was delighted that he received his aunt's letter.

2.=> People recycle old car tires to make shoes and sandals.

3.=> I'm very sad not to accept in that group.

4.=> I haven't spoken to her for three years.

5.=> My father asked.me to turn down the radio for him.

6.=> It is Lan's.fifteen birthday next week.

7.=> When did you use the pen?

=>
3. He was delighted that he received his aunt's letter.
4. People recycle old car tires to make shoes and sandals.
5. I'm very sad not to be accepted in that group. 
6. Van is always forgetting his homework.
7. Do you mind helping me to put the chairs away?
8. I'd rather you didn't make any noise.
9. It is very interesting to have a vacation abroad.