I was really anxious about you. You _______ home without a word.
| A．mustn’t leave | B．shouldn’t have left | C．couldn’t have left | D．needn’t leave |
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 |
Carl wanted to play a joke on Bob but gave himself _____ by laughing.
| A．away | B．in | C．out | D．up |