These compounds could not have been formed if the chemical reaction ______ stopped.

admin2013-05-22 50

问题 These compounds could not have been formed if the chemical reaction ______ stopped.

选项 A、have been
B、has been
C、had been
D、were

答案C

解析虚拟语气题。主句中是 could have done，相对应的 if 引导的条件状语从句中的时态应为过去完成时 had done，是对过去已发生事情的虚拟。本句大意为：若是当时化学反应被中止，这些化合物就无法形成。

转载请注明原文地址:https://kaotiyun.com/show/Q0eC777K

英语

相关试题推荐

随机试题

最新回复(0)