The roof fell ____ he had time to rush out.
| A．until | B．before | C．when | D．Since |
Once out of the earth’s gravity, the astronaut is by the problem of weightlessness.
| A．affected | B．effected |
| C．related | D．offered |
The doctor telephoned to say that he couldn’t ____ the meeting because he had to ___ a patient.
| A．came to; attend to | B．attend; attend |
| C．join; treat | D．attend on; look after |
When we are in a new place, we must __our manners and try to follow the customs of the place.
| A．look out | B．keep eyes out | C．mind | D．put up with |
In the early morning all of us stood at the top of the mountain __ east of the city, watching _____burning sun rising.
| A．/; a | B．the; a | C．the; the | D．/; the |
The boy was led ___while crossing the road.
| A．in the hand | B．by his hand | C．by hand | D．by the hand |