The boy seized a stick and ___ the dog, but it ran away.
| A．beat | B．struck at | C．hit | D．knock at |
Though they met for the first time, they talked __________ they were good friends.
| A．even if | B．as if | C．even though | D．if only |
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 |