The field research will take Joan and Paul about five months;it will be a long timewe meet them again.
| A． | after | B． | before |
| C． | since | D． | when |
________, I think, and the problem could be settled.
| A．So long as you keep up your spirits | B．A bit more effort |
| C．If you doubt your efforts | D．Making great efforts |
My careless friend Bob received a ticket for speeding. He ____ have driven so fast.
| A．can’t | B．wouldn’t | C．mustn’t | D．shouldn’t |
The flu is believed ____by viruses that like to reproduce in the cells inside the human nose and throat.
| A．causing | B．being caused | C．to be caused | D．to have caused |
Seeing her father come back, _________.
| A．tears ran down her cheeks | B．Her tears ran out |
| C．she burst into tears | D．She burst into crying |
The old woman stood still with her eyes _________ the picture.
| A．fixing in | B．fixing on | C．fixed in | D．fixed upon |