A man escaped from the prison last night. It was a long time ______ the guards discovered

外语类 2019-12-19 01:43:51 公共英语已帮助人

A man escaped from the prison last night. It was a long time ______ the guards discovered what had happened.

A．before

B．until

C．since

D．when

请帮忙给出正确答案和分析，谢谢！

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正确答案：A
解析：before用在复合句中，通常强调主句动作发生在从句动作之前，表示“先……再……；先……然后……；而后”，如；All things are difficult before they are easy．诸事先难后易。Before I could understand the first question，the teacher had begun the second one．我还没理解第一个问题，老师已开始讲第二个问题了。