1 . I was cutting my rose bushes _____ someone knocked on the front door. Was it you?

A．as

B．when

C．while

D．before

2 . She explains English grammar   _________ clearly that even I can understand it.

A．such

B．what

C．how

D．so

3 . How excited I am now! You know, it is the second time that I _____ the first prize in the 400-meter race.

A．wins

B．won

C．have won

D．is winning

4 . The more we can enjoy what we have, the _____ we are.

A．happier

B．happiest

C．more happily

D．most happily

5 . –Would you like some candies?
–_______. I have got a sweet tooth.

A．Better not	B．It’ s up to you
C．Oh, that’ s too bad	D．That couldn’ t be better

6 . They are ________ little birds that we can’t see them in the sky.

A．such	B．very
C．so	D．too

7 . —Have you come to our town before?
—No, this is the first time I _______ here.

A．was	B．have been
C．came	D．am coming

8 . —Mr. Smith must know a lot about Chinese history.
—_______. He has studied it for years.

A．So he does	B．So does he
C．So he must	D．So must he

9 . We were swimming in the lake ______ suddenly the storm started.

A．until

B．while

C．when

D．before

10 . ﹣Do you mind _____ alone at home？
﹣No， but I want a good book _____．（　　）

A．leaving； to read	B．to be left； reading
C．to leave； reading	D．being left； to read