问题补充：
It was back home after the experiment.
A. not until midnight did he go
B. until midnight that he didn’t go
C. not until midnight that he went
D. until midnight when he didn’t go
答案：
A. not until midnight did he go
B. until midnight that he didn’t go
(答案→)C. not until midnight that he went
D. until midnight when he didn’t go
解析：此题考查的是not…until句型的强调结构，其最根本结构是：He did not go back home after the experiment.①,把①转变为Not until midnight did he go back home after the experiment.②,注意②中的倒装结构，把②中划线部分放在强调结构It be 被强调部分that…中进行强调，但注意that从句后面不用倒装形式。
