until/not until是指：直到什么时候为止...其中非延续性动词用后者，延续性动词用前者。
例句：Not until my father came back did I fell asleep.
I was awake until my father came back.
注意：倒装时倒装主句，从句语序不变。改为强调句时基本语序不变。
before在...之前，常用在时间状语从句中。
常用句型：It is +( )+before...
注意：前后时态要一致，遵从主将从现原则。
翻译：1...就...It was not long before he turned against his country.不久他就背叛了他的祖国。
2...才...It was a long time before he came to himself.很久之后他才恢复意识。
这是我的珍贵的笔记，全打给你了，累...希望能帮上忙
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