3.1)Comrade Li joined the Party more than/over twenty years ago.

2)It is already more than/over twenty years since Comrade Li joined the Party.

2.1)Let's go out for a walk,shall we?

2)What/How about going out for a walk?

3)Shall we go out and take a walk?

1.October 1/lst /First is our National Day.

1.at/inschool　　　　　　　　　 2.a lot ofquestions

3.with his lessons　　　　　　　 4.worth teaching

5.everhad/got/received　　　　　 6.She taught/helped him

7.for/on grown-ups　　　　　　　 8.he was ten

9.grew/planted vegetables　　　 10.buy/get the chemicals

16.(C)　　 17.(B)　　 18.(C)　　 19.(B)　　 20.(D)

11.(D)　　 12.(D)　　 13.(B)　　 14.(A)　　 15.(D)

6.(C)　　　 7.(A)　　　 8.(D)　　　 9.(C)　　　 10.(B)

1.(B)　　　 2.(C)　　　 3.(A)　　　 4.(B)　　　 5.(A)

5.What do you usually do before breakfast?

4.How often(或How many times a week)did Mr Green give her piano lessons?