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 |
Something must be done to prevent our city ____ by thick smoke.
| A．to be polluted | B．from polluting | C．from being polluted | D．polluting |
To tell you the truth, I have nothing to do ____ it.
| A．about | B．with | C．for | D．of |
Did you have any trouble ____ the post office?
| A．to have found | B．with finding | C．to find | D．in finding |
- How long has the bookshop been in business?
-____1982.
| A．After | B．In | C．From | D．Since |
He looked quite healthy ____ he was ____ the age of seventy.
| A．when; at | B．because; in | C．if; for | D．though; at |