So sudden（）that the enemy had no time to escape.
| A． | did the attack | B． | the attack did | C． | was the attack | D． | the attack was |
There has been ____rising demand for grain as ____industrial material in spite of the nation’s good harvests.
| A．/;an | B．a;an | C．the;an | D．a;/ |
He wondered if he could slip out of the lecture hall without anyone______.
| A．noticing | B．noticed | C．to notice | D．being noticed |
We cannot figure out ____quite a number of insects, birds, and animals are dying out.
| A．that | B．as | C．why | D．when |
We have been told that under no circumstances_______ the office telephone for personal affairs.
| A．may we use | B．we can use | C．we could use | D．did we use |