_ your help, we’d never have been able to get out of trouble.
| A．Had it not been |
| B．If it was not |
| C．If we had not been |
| D．If there has not been |
_____ from heart trouble for years, Professor White has to take some medicine with him wherever he goes.
| A．Suffered | B．Suffering |
| C．Being suffered | D．Having suffered |
----_____I return the dictionary within three days?
----No, you_____. You_____ it for five days.
| A．May; needn’t; can borrow | B．Can; mustn’t; would have |
| C．Must; don’t have to; can keep | D．Shall; can’t; should read |
Controlling water-pollution is necessary_____ it will be expensive.
| A．so that | B．as if | C．even though | D．ever since |
Such a person _____ you talked about is seldom seen now.
| A．that | B．whom | C．who | D．as |
_______ the teacher’s instruction in the lab_____ important.
| A．Following; are | B．Following; is | C．Followed by; are | D．To follow; are |