"it is not until"倒装句在英语中非常常见，其结构为：it is not until + 时间状语 + 主语 + 动词。这种句型可以清晰地表达某事直到某时间或条件满足后才发生。此外，它还有一种否定形式，即：it was not until + 时间状语 + that + 主语 + 动词。这种句型在英语语法中非常实用，通过多加练习，可以更准确地表达意思。
首先，it is not until倒装句的结构为：it is not until + 时间状语 + 主语 + 动词。
例如：
- It was not until I arrived at the airport that I realized I had forgotten my passport.
- It is not until you lose something that you realize its true value.
在it is not until倒装句中，时间状语通常放在句首，而主语和动词的位置则颠倒过来。这种句型的用法，可以帮助我们在表达某个事情直到某个时间才发生或某个条件满足后才会发生时，更加清晰地表达自己的意思。
此外，it is not until倒装句还有一种否定形式：it was not until + 时间状语 + that + 主语 + 动词。
例如：
- It was not until I had finished my work that I relaxed.
- It was not until I got home that I realized I had left my keys at the office.
在这种形式的句子中，that引导了一个宾语从句，主语和动词的位置恢复正常。
