Ответ:
1. Sorry, I didn't tell you about my cowardice - I was too shy.
2.The cost is very high.
3. He doesn't play football.
4. I don't know how to dance.
5. The museums are very nice in this city.
6. I am making a cup of tea for my wife.
7. She works very hard, but her brother doesn't work at all!
8. She didn't want to come to my party.
9.This childish joke wasn't so smart.
10. My colleague doesn't expect this brilliant idea.