It took a long time for the effective use of natural gas ______.
| A．making | B．being made | C．to make | D．to be made |
Some schools will have to makein agreement with the national soccer reform.
| A． | judgments | B． | adjustments |
| C． | comments | D． | achievements |
The police officers decided to conduct a thorough andreview of the case.
| A． | comprehensive | B． | complicated |
| C． | conscious | D． | crucial |
The real reason why prices ____ , and still are, too high is complex, and no short discussion can satisfactorily explain this problem.
| A．were | B．will be |
| C．have been | D．had been |
The whole team _____ Cristiano Ronaldo, and he seldom lets them down.
| A．wait on | B．focus on |
| C．count on | D．call on |
It might have saved me some trouble ______ the schedule.
| A．did I know | B．have I known |
| C．do I know | D．had I known |