Exercise 1

1.C

2.B
3.A

4.A

5.B

Exercise 2

1.cleverest

2.longer

3.best

4.cleaner

5.more expensive

6.more quick

7.more dangerous

8.sweeter

9.more exciting

10.faster

11.most popular

12closest 

13.beautiful-most beautiful

14.hotter

15.worse

16.better

17.biggest-bigger

18.more difficult-most dificult

19.largest

16c

17b

18a

19 a hoặc c

20b

exercise 2:

1 cleverest

2 longer

3 the best

4 cleaned

5 more expensive

6 quickly

7 more dangerous

8 sweeter

9 the most exciting

10 fastest

11 the most popular

12. closed

13.beautiful

14. hotter

15 worse

16 better

17big/bigger

18 more difficult/  most difficult

19 largest