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：本题考查强调句。强调句与not until构成It was/ is not until.... that....固定的强调句句型，故选C。
