【题目】If it _____ earlier, the printing machine would not have broken down．
A．has been repaired B．is repaired
C．had been repaired D．was repaired
在线课程【答案】C
【解析】If+主语+had done，主语+would/should have done。表示对过去虚拟。根据主句是对过去的假说，即印刷机坏了却说“应刷机就不会坏了”（“he printing machine would not have broken down”），该从句是对过去的虚拟。