“Not all my friends smoke” means :____.
| A．None of my friends smoke | B．All my friends smoke |
| C．Some of my friends smoke | D．My friends don’t smoke |
30．—Peter looked tired and a little absent-minded at the meeting．
—He _____ up too late．
| A．may stay | B．could stay |
| C．should have stayed | D．must have stayed |
29．His humorous closing speech was a welcome addition to the ______dull meeting．
| A．therefore | B．meanwhile | C．otherwise | D．Thus |
28．The government had hoped to draw as much attention as possible to this problem but it didn't ______ that way．
| A．work out | B．give out | C．go out | D．pick out |
27．The students wonder______ good the course will do to their future jobs．
| A．which | B．what | C．whether | D．Why |
26．He never regretted the anxious hours he had had ______ for the missing papers．
| A．search | B．searching | C．searched | D．to search |