I. làm đúng r
II. 
1. B - nhấn âm 2
2. B - âm 2
3.D - âm 3, còn lại 2
4.B. - âm 3, còn lại 2
III.
1.D  2.D  3.B   4.B  5.D  6.A   7.D   8.A   9lD   10.D   11.A     12.B   13.A     14.B   15.C   16.B -> turn down = từ chối    17.C   18.A

- Đặt ra những chính sách giảm giảm sinh những đảm bảo quy mô dân số với xu thế giảm sinh vững chắc.

- Nâng cao chất lượng dân số với những người dân ít học, thất học, sống ở vùng sâu, vùng xa

- Khuyến khích kết hôn ở độ tuổi thích hợp và ủng hộ xây dựng quy mô gia đình ít con. Xóa bỏ thành kiến trọng nam khinh nữ nhằm duy trì sự cân bằng về tỷ lệ giới tính.

- Giáo dục giới tính cho trẻ tuổi vị thành niên, nâng cao hiểu biết về sinh sản.

1.a. In
2. b. used to
3. b. to move
4. d
5. a
6. c

1. Bỏ the -> In the past, some ethnic groups lived semi-nomadic life.
2. People + s -> The peoples of Viet Nam are diverse but very peaceful.
3. Equal -> equality => All the ethnic peoples of Viet Nam have equality in every field.
4. Built -> been built => Many special schools have been built to improve the education standards of ethnic people.
5. Other -> another => Although they speak different languages, the ethnic groups in this region live near one another.
6. To -> for => The communal house is used for village meetings or as a place of worship.
7. Dense -> densely => A village is less densely populated than a city.
8. Home-make -> home-made => I like the street markets where the locals sell their home-made products.
9. For -> against => In our country, it is against the law to discriminate against any ethnic or religious group.
10. Writing -> written => Many ethnic groups have their own languages, and some even have written languages.

1. If he is selfish, I won't like him.
2. If you don't run fast, you'll not catch the train.
3. If you don't review your lesson, you will get bad marks.
4. You will be ill if you smoke too much.

The last time we jogged was in August.

1. She always doesn't talk in class.
2. How many students are there in your school?
3. Peter can't draw.
4. Did they do homework last night?
5. Do you love your sister very much?

Exercise 24)
1. She needs to buy a new house.
2. I would like to drink white coffee. 
3. Would you like to go to the cinema with me tonight :>>?
4. She is able to speak English well
5. I’m delighted to get good marks.
6. It takes me two hours to go jogging every day.
7. My father always asks me not to stay up late.
8. Don’t forget to turn off the dripping faucet.
9, Remember to phone me at 6 o’clock tonight.
10. In Viet Nam, people enjoy reading newspapers and magazines.
11. She enjoys drinking milk. 
12. Would you mind closing the door? 
13. Do you mind helping me to do this exercise?
14. What about playing tennis?
15. How about watching the newsreel on TV
16. We suggest saving energy.
17. We suggest protecting our environment.
18. I suggest putting garbage bins around the schoolyard.
19. We’re all looking forward to hearing from you soon.
20. I’m looking forward to receiving your letter. 
21. I look forward to meeting you soon
22. How many hours a day do you spend doing homework? 
23. I am interested in reading novels.
24. Let’s go to a picnic this weekend.
25. Shall we listen to music tonight?
26. Why not we take part in these cultural activities?
27. Why not we save energy?
29. Why not we protect our environment.
30. How about using public buses instead of motorbikes to reduce exhaust fume?
Chúc cậu hc tốt nha =)

Exercise 23)

19. Phone -> phoning

20. Do -> doing

21. Watch -> watching

22. To go -> going

23. To listening -> listening

24. Save -> saving

25. To protect -> protecting

26. Get -> getting
27. Hear -> hearing

28. Receive -> receiving

29. Meet -> meeting

30. Buy -> buying

31. Watch -> watching

32. Play -> playing

33. Wash -> washing

34. Learn -> learning

35. To sing -> sing

36. To smoke -> smoke

37. Working -> work

38. Doing -> do

39. Telling -> tell

40. Eating -> eat

41. Skipping -> skip

42. Catching -> catch

43. Watching -> watch

44. To go -> go

45. Listening -> listen

46. To save -> save

47. To protect -> protect

48. To prepare -> prepare

Vì x = 4 nên x + 1 = 5
A = (x+1)x⁵ - x⁴(x+1) + x³(x+1) - x²(x+1) + x(x+1) - 1
= x⁶ + x⁵ - x⁵ - x⁴ + x⁴ + x³ - x³ - x² + x² + 1 - 1
= x⁶ + 1 - 1
Thay x = 4 vào A ta có:
A= 4⁶  + 1- 1
= 4096