如何对not… until…句式进行强调

如何对not… until…句式进行强调
 
对not…until句式的强调有固定的句型，即It is / was not until…that…如：
It was not until yesterday that I noticed it. 直到昨天我才注意到此事。http://yingyu.chazidian.com
It was not until I saw Mary that I felt happy. 直到见到玛丽我才高兴起来。
It was not until you had explained how that I managed to do it. 直到你给我解释了理由，我才会做的。
It was not until she took off her dark glasses that I realized she was a famous film star. 直到她取下墨镜，我才意识到她是一位著名影星。
It was not until I met you that I knew real happiness. 直到我遇到你以后，我才真正体会到幸福。
It was not until you had explained how that I managed to do it. 直到你给我解释了理由，我才会做。
请看两道题：
(1) It _______ we had stayed together for a couple of weeks _______ I found we had a lot in common.
A. was until; when                                  B. was until; that
C. wasn’t until; when                              D. wasn’t until; that
答案为D。此题考查not…until…句式的强调形式——It was not until…that…的用法。注意不要想当然地将其中的that换成when。
(2) It was not until she got home _______ Jennifer realized she had lost her keys.
A. when                                                  B. that 
C. where                                                 D. before
答案为B。考查not…until…的强调形式，其基本结构为it was not until….that…形式。