Ответ:
1. Have you ever been to London?
2. What is your telephone number?
3. We are going to play chess this afternoon.
4. I prefer buying clothes from boutiques.
5. We were talking when the telephone rang.
6. She had finished cooking before we came.
7. How much dollars do you spend a week?
8. Who plays the violin?
9. I am going to fly to o NY next month.
10. They don't enjoy loud parties.
11. What do you mean?
12. I don't understand the plan.
13. The soup smells really good.
14. She has won the prize.
15. How much does it cost?
16. I think he is a very intelligent boy.
17. It often rains in Autumn.
18. Look! The children are playing outdoors.
19. She wants to improve her pronunciation.
20. I've been waiting for you at the station.
or
I'll be waiting for you at the station.