11. They prefer to listen to pop music.
12. I am interested in these historical places.
13. You ought to go to bed early.
14. You ought not to stay up late
15. Children should take part in outdoor activities with their friends.
16. You should do your homework carefully.
17. The doctor told Lan to brush her teeth after meals.
18. I didn't go to school yesterday because I had a bad cold.
19. She likes playing badminton.
20. I prefer pop music to jazz music

11. They prefer listening to pop music
12. I'm interested in the history of these places.
13. You ought to go to bed early
14. You ought not to stay up late
15. Children should take part in outdoor activities with (their) friends
16. You should do homework carefully
17. Doctor told Lan to brush her teeth at meals
18. I didn't go to school yesterday because I have had a bad cold
19. She likes playing badminton
20. I prefer pop music to jazz music.
 

11. They prefer to listen to pop music.
12. I am interested in these historical places.
13. You ought to go to bed early.
14. You ought not to stay up late
15. Children should take part in outdoor activities with their friends.
16. You should do your homework carefully.
17. The doctor told Lan to brush her teeth after meals.
18. I didn't go to school yesterday because I had a bad cold.
19. She likes playing badminton.
20. I prefer pop music to jazz music