The Great Wall winds its way _____ mountains _____ valleys and _____ deserts to the east.
| A．over; in; through |
| B．over; through; across |
| C．on; in; across |
| D．in; in; through |
________ is a very popular sport in summer.
| A．Swim | B．Go to swim | C．Go swimming | D．Swimming |
John failed in the exam, ________he had prepared a lot for it before.
| A．as | B．when | C．once | D．although |
—______ have you studied English?
—For six years.
| A．How long | B．How soon |
| C．How often | D．How far |
Nuclear radiation is said __________ the biggest health challenge in Japanese Earthquake over the past few months．
| A．being | B．to be | C．to have been | D．that it is |
They must have been enjoying themselves there，or they __________ so long．
| A．wouldn’t stay | B．needn’t have stayed |
| C．wouldn’t have stayed | D．couldn’t stay |