____is certain is ___prevention is more important than treatment .
A．It;that  |
B．What;that | C．As;what | D．What;what |
—I telephoned him twice and I couldn’t get through to him．
—The line might have been out of order, _________?
| A．don’t you | B．do you |
| C．wasn’t it | D．hadn’t it |
The USA has a quarter of the leading 200 in the latest ranking of the world universities, _________ 30 of the universities are in the UK．
| A．when | B．while | C．where | D．why |
Our school appeals to the students to _________ at least an hour every day to take exercise in order to raise learning efficiency．
| A．set aside | B．pick out |
| C．take up | D．keep back |
Some of the members demanded to know why they had been kept _________ the true facts until they reached the present critical stage．
| A．in view of | B．in honor of |
| C．in place of | D．in ignorance of |
—What do you think of the conditions here?
—Oh, wonderful! _________ a better hotel．
| A．Seldom we can find | B．Rarely do we find |
| C．Never will we find | D．Hardly can we find |