---Sorry, sir. I can't answer this question.
---Well, you are supposed ______ this part of history.
| A．reading | B．to be reading | C．to read | D．to have read. |
Mark was a student at this university from 2006 to 2011，________he studied very hard and was made Chairman of the Students’ Union.
| A．during which time | B．for which time | C．during whose time | D．by that time |
Liu Xiang is believed _____ over $ 20 million in advertisements last year alone.
| A．to earn | B．have earned | C．to have earned | D．having earned |
The _______ boy made the police and his family _______.
| A．gone; puzzled | B．missing; puzzled | C．missing;puzzling | D．lost; puzzling |
Kathy ______ some French while she was away on a business trip in France.
| A．picked up | B．took up | C．made up | D．turned up |
Scientists are convinced _____ the positive effect of laughter _____ physical and mental health.
| A．of; at | B．by; in | C．of; on | D．on; at |