b 

1. c

2. d

3. d

4. b

5. d

6. b

7. c

8. c

9. d

10. b

11. a

12. b

13. d

14. b

15. a

16. c

17. c

18. a

19. c

20. c

21. d

22. c

23. a

24. c

1. b

2. d

3. c

4. a

5. a

6. d

7. c

8. a

9. a

10. d

11. d

vật lí : cắt giấy, tuyết rơi, sương mù

hoá học : đốt giấy, cháy rừng

a

3. b

4. b

5. a

6. b

7. b

8. a

9. b

10. a

2. some years ago the laboratory in my school was worse equipped than now

3. quang works harder so he often gets better marks than nam

4. minh drives more carelessly than trung so he often has had an accident

5. going by a bus is slower than going by a taxi but it costs less than a taxi

had

ix.

1 : i have bought a laptop but i haven't used it

2 : i have written a log but i haven't uploaded any photos it

3 : we started the game half an hour ago but we haven't finished it

4 : my dad have been going to london but he hasn't seen the big ben

5 : i have read my english book but i haven't done my english homework

6 : they have lunch but they haven't dinner

7 : i have downloaded some songs but i haven't listened to them

x :

1 : this weather is not good for a camping holiday

2 : nam's mother needs some vegetables and a half kilo of tomato

3 : what do you want to buy, mum ?

4 : ha's sister is listening to music in the room at the moment

5 : miss thuy is washing her hair because she is going to the party tonight

6 : he doesn't have much time to write to his friend

7 : there is a small park in front of linh's house

ii. past simple

1. had

2. read

3. makes

4. helps

5. sends

6. called

7. didn't feel

8. did you move

9. had been

10. were