If I hadn’t been lucky enough to meet you. I really _____ what I would have done.
| A．don’t know | B．hadn’t known |
| C．wasn’t knowing | D．wouldn’t know |
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 |
This photo of mine was taken _______ stood the famous Eastern Bright Pearl in Shanghai.
| A．which |
| B．in which |
| C．where |
| D．there |