19、A man cannot smile like a child,_________a child smiles with is eyes,while a man smiles with his lips alone.

A.so               B.but           C.and              D.for

18、I was giving a talk to a targe group of people,the same talk I __________to half a dozen other groups.

A.was giving        B.am giving     C.had given         D.have given

17、Fred,who had expected how it would go with his daughter,had a great worry________his mind.

A.on              B.in            C.with             D.at

16、As the busiest woman in Norton,she made_________her duty to look after all the other people’s affairs in that town.

A.this              B.that           C.one             D.it

15、________achievement,last week’s ministerial meeting of the WTO here camed a low,though not failing ,grade.

A.In terms of       B.In ease of        B.As a result of       D.In face of

14、If you think that treating a woman well means always_______her permission for things,think again.

A.gets             B.got             C.to get              D.gutting

13、Although she did not know Boston well,she made her way________ to the Home Cirele Building.

A.easy  enough     B.enough easy     C.easily enough      D.enough easily

12、We saw several natives advancing towards our party, and one of them came up to us.________we gave one bells and glasses.

A.to which         B.to whom         C.with whom          D.with which

11、I had just stepred out of the bathroom and was busily drying myself with a towel_________I heard the steps.

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

10、把小白兔控制血红蛋白合成的mRNA 加入到大肠杆菌的提取液中，结果能合成出小白兔的血红蛋白，这说明

A. 小白兔的RNA能指导大肠杆菌的蛋白质合成    

B. 生物共用一套遗传密码子

C. 大肠杆菌的遗传物质是RNA         

D. 小白兔控制血红蛋白合成的基因能进入大肠杆菌