Only outside the Earth抯 atmosphere _____ to attain extremely high velocities.

[　　]

A． to be safe for a space vessel　 B． is it safe for a space vessel

C． for a space vessel to be safe　 D． a space vessel to be safe

A flying stone _____ him on the head and knocked him out.

[　　]

A． beat　B． hit　C． struck　 D． flogged

－- Must I stop the machine when I change the speed?

－- Yes, you _____. Otherwise there will be serious damage to the engine. But you ____ switch off the power.

[　　]

A． must , needn抰　　 B． ought to , shouldn抰

C． should , don抰 have to　 D． have to , might not

Man: I agreed with your proposal at the meeting this morning. It was a good one.

Woman: You should have backed me up then　－－ when I needed it.

Question: What does the woman mean?

[　　]

A． her back hurt during the meeting.

B． She agreed that it was a good meeting.

C． The proposal should be sent back.

D． His support would have helped this morning.

Some research has shown that many assembly line occupations are unskilled, poorly paid, _______.

[　　]

A． prestige is lacking　　　B． and lacking in prestige　

B． and the lack of prestige　　D． lack prestige in

The first active step in vision is the absorption of light by a photosensitive substance, _____ .

[　　]

A． is a visual pigment　B． pigment that visual　

C． a pigment is visual　D． a visual pigment

_____ her death in 1886 , the poet Emily Dickinson had become a legend in her hometown of Amherst , Massachusetts .

[　　]

A． It was before long　B． Before long

C． When long before　D． Long before

A vaccine ______ to manufacture substances called antibodies that fight bacteria, toxins , and viruses.

[　　]

A． causes the body　 B． of the body causing

C． caused by the body　D． the body causes

Could you tell me the _______ of the professor who spoke to us the other day?

[　　]

A． district　 B． area　C． address　D． location

We all ____ her good fortune.

[　　]

A． learn　B． study　 C． admire　 D． envy