—Time flies! The wonderful party is over. We'll have to part.
—No need to feel blue. _________
| A．A still tongue makes a wise head. | B．A single flower does not make a spring. |
| C．All good things come to an end. | D．All that glitters is not gold. |
________ it is, the boy never seems to be able to finish it off.
| A．However interesting a book |
| B．Whatever interesting a book |
| C．How interesting a book |
| D．What an interesting book |
The new system needs to be in operation for five months ________ it can be updated.
| A．as | B．while |
| C．before | D．once |
We can't wait any longer ________ we'll miss the plane.
| A．or | B．but |
| C．so | D．yet |
House prices vary from place to place and are usually high ________ there are famous schools.
| A．when | B．since |
| C．where | D．whether |
It will be another 50 years ______ our country is expected to reach the level of a medium developed country.
| A．since | B．before |
| C．that | D．when |