来源：学生作业帮 编辑：拍题作业网作业帮 分类：英语作业 时间：2024/05/09 20:05:50
请教道英语语法的问题.
3.It was ______ the policeman came ______ the parents knew what had happened to their son.(选C)
A.before...as B.until...when C.not until...that D.until...that
句子整体上是一个强调句型：it is.(强调部分)that...
强调部分是一个not until 句型
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