—You never think of others ! You kept me waiting for two hours.
—I’m sorry that you _________ think so.
| A．would | B．could | C．might | D．should |
To enjoy the scenery,Irene would rather spend long hours on the train _______ travel by air.
| A．as | B．to |
| C．than | D．while |
The pianist waited for silence a while _______ he began to play the violin.
| A．until | B．when |
| C．after | D．before |
Scientists say it may be five or six years _______ it is possible to test this medicine on human patients.
| A．since | B．after |
| C．before | D．when |
It was some time _______ we realized the truth.
| A．when | B．until |
| C．since | D．before |
Roses need special care _______ they can live through winter.
| A．because |
| B．so that |
| C．even if |
| D．as |