9. I think living in the country is less polluted than living in the city

10. They say finding a job here is difficult

11. He thought his bike was broken by us

12. It took Hoa 3 days to learn swimming

13. His exercise is being done by Hung at the moment 

14. He rode the bike to the zoo

15. He has collected stamps for 10 years

16. The last time I saw her was when she left school

17. What is the book's price?

18. Our class has 20 boys

9.=>I think living in the country is cleaner than living in the city.

10.=> They say a job is difficult to find here.

20.=>Our class have 20 ...(chữ đừng sau số 20 mình ko nhìn rõ)

17.=>What is the price of this book?

16.=>The last time I saw her was when she left school.

mấy câu còn lại mình khum biết,mong bạn thông cảm mình hơi dốt tiếng anh:(!!