21.-I am going to the post office.

-________you’re there,can you get me some stamps?

A.As　　　　　 B.While　　　　　 C.Because　　　 D.If

20.Scientists say it may be five or six years________it is possible to test this medicine on human patients.

A.since　　　　 B.after　　　　　　 C.before　　　 D.when

19.________modeling business is by no means easy to get into,the good model will always be in demand.

A.While　　　　 B.Since　　　　　 C.As　　　　　 D.If

18.________the stars are,the smaller they look,as is known to all the people.

A.The farther away　　　　　　　　　 B.Farther away

C.No matter how far away　　　　　　 D.If farther away

17.The action of the play is________the struggle between the two women.

tred on　　　　　　　　　　　 B.situated in

C.located in　　　　　　　　　　　 D.focus on

16.How to protect the right of the Aborigines best________a challenge for the present Australian government.

A.stays　　　　 B.remains　　　　　 C.stands　　　　 D.keeps

15.Robert’s red hair made him________in a crowd.

e out　　　　　　　　　　　　　 B.stand out

e up　　　　　　　　　　　　　 D.stand up

14.Tom would like to find somewhere to work because he can not________the boss.

e up with　　　　　　　　　　　 B.catch up with

C.keep up with　　　　　　　　　　　　 D.put up with

13.We’d better wait until your sister arrives,________?

A.hadn’t we　　　 　　　　　　　　　　B.wouldn’t we

C.didn’t we　　　　　　　　　　　　 D.haven’t we

12.It’s better to concentrate on a few things rather than________so much at one time.

A.to attempt　　　　　　　　　　　　 B.to intend

C.attempting　　　　　　　　　　　　 D.intending