21. My bag
22. your 
23. activity
24. activity
25. performances

33. the doctor told him to go to bed soon

34. the teacher told her sts to do all exercises before going to school

25. most people are interested in sending greeting cards to their friends at christmas

36. He is going to go travel around america next month

Trùng roi di chuyển cơ thể bằng cách dùng roi xoáy vào nước.
=> Trùng roi di chuyển nhờ sử dụng cái roi của nó

(x-1)⁹: (x-1)⁷.(x-1)=27²
(x-1)⁹:(x-1)⁸=729
x-1=729
x=730
vậy x=730
 

2. more boring
3. busier
4. bigger
5. more interesting
6. noisier
7. more expensive
8. cheaper
9. more comfortable
10. more beautiful
11. more intelligent
12. longer
13. larger
14. stronger
 

13. I am a teacher, and she is, too
14. She is twenty, and so is Lan
15. My brother can play the piano and so do they
16. We can dance, and so do I
17. Teo and Ti like tea, and i do, too
18. We play table tennis, and so do they
19. I can ride a bike. They do, too
20. I drink cold water. So does sh
21. Tom plays football well, so does Tim
22. I will go to school tommorow, so will he
23. The sts are kind, I am, too
24. I have english class on Mondays, Lan does, too