1.It's vey impotant to keep the environment clean.

2.The time machine to the public will be shown when they finish it.

3.He was delighted that his aunt sent him a letter.

4.People recycle old car tires to make shoes and sandals.

5.I'm vey sad not to accept in that group.

6.I haven't spoken to her for three years.

7.Tam used to type fast.

8.My father asked me to turn down the radio.

9.It is Lan's fifteenth birthday next week. 

10.When did you use the pen?

1. It's very important to keep the environment clean

2. The time machine will show to the public when they finish

3. He was delighted that his aunt sent the letter to him

4. People recycle old car tires to make shoes and sandals

5. I'm very sad not to accepted in that group

6. I haven't speak to her for 3 years

7. Tam used to type very fast

8. My father asked me to turn down the radio for him

9. It is Lan's fifteenth birthday next week

10. When did you use the pen?

Bạn ơi, xin lỗi bạn rất nhìu nhưng về câu 3 muk ko chắc là mik có làm đúng hay ko. Còn những câu còn lại thì bạn cứ yên tâm :3