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 |
I'm sorry you've been waiting so long，but it'll still be some time ________ Brian gets back.(2008·北京)
| A．before | B．since | C．till | D．after |
He had no sooner finished his speech________ the students started cheering.(2011·辽宁)
| A．since | B．as |
| C．when | D．than |
He smiled politely ________ Mary apologized for her drunken friends.(2012·山东)
| A．as | B．if | C．unless | D．though |
________ we have enough evidence，we can't win the case.
| A．Once | B．As long as | C．Unless | D．Since |
He is so busy.He cannot afford enough time with his son________he wants to.
| A．even if | B．as if | C．because | D．before |