The meeting was expected to start at 9 o'clock but the manager didn't turn up ______ twenty minutes later.
| A．before | B．until | C．after | D．since |
Much to ________ surprise of the students, the concert which was held once a year turned out to be ________ complete failure.
| A．/; a | B．the; a | C．the; / | D．/; / |
Scientists say it may be five or six years _______ it is possible to test this medicine on human patients.
| A．since | B．after | C．before | D．when |
He has the habit of ________ useful information while reading.
| A．getting down | B．setting down | C．going down | D．bringing down |
He left Wenzhou for Beijing last year, and we ________ him ever since.
| A．hadn’t seen | B．haven’t seen | C．didn’t see | D．wouldn’t see |
When the boss got to the factory ________ midnight, he found it ________ ruins.
| A．on; in | B．at; under | C．at; in | D．on; under |