It was dark______ we arrived at the little town .
| A．that | B．until | C．since | D．before |
The new safety regulations were agreed on after _____ with the work-force.
| A．conference | B．participation |
| C．intervention | D．consultation |
His test results are not very _____. He does well one week and badly the next.
| A．invariable | B．consequent | C．continuous | D．consistent |
Scientists think they have _____ in their attempt to find the causes of some major dieases.
| A．broken through | B．worked out |
| C．fallen out | D．got round |
If you ever have the _____ to go abroad to work, you should take it.
| A．possibility | B．offer | C．luck | D．chance |
In aerospace devices the weight of the necessary power producing equipment is _____.
| A．vital | B．possible | C．capable | D．reliable |