It was __________ back home after the experiment .
| A．not until midnight did he go | B．until midnight that he didn’t go |
| C．not until midnight that he went | D．until midnight when he didn’t go |
I'll start early, _________ I oversleep.
| A．unless | B．though |
| C．if | D．whether |
I insisted that a doctor _________ immediately.
| A．has been sent for | B．sends for |
| C．will be sent for | D．be sent for |
His pale face suggested that he _________ frightened.
| A．be | B．was |
| C．would be | D．were |
We are all for your suggestion that the meeting _________.
| A．be put off | B．was put off |
| C．should put off | D．is to put off |
—The experiment had failed. —I suggest you _________ again.
| A．try | B．trying |
| C．will try | D．would try |