-We'll go to the party to be held in the Grand Theater at 8： 00tonight. Could you join us?
-I'm afraid I can't. I __________ the paper with my instructor.
| A．am discussing |
| B．have discussed |
| C．will be discussing |
| D．will have discussed |
The medicine works more effectively __________ you drink some hot water after taking it.
| A．as | B．until | C．although | D．if |
It will be a long time __________ we finally solve the problem of pollution.
| A．before | B．since | C．when | D．Until |
It was five o'clock in the afternoon __________ they climbed up to the top of the mountain.
| A．since | B．when | C．that | D．until |
—Did you remember to give Tom the book you borrowed from him?
—Yes, I gave it to him __________ I saw him.
| A．while | B．the moment | C．as | D．once |
Busy __________ she is, Rita sets aside two hours every Sunday afternoon to spend with her son.
| A．although | B．as | C．while | D．even if |