1）强调句型的强调部分必须是对 that / who 之后句子的某一成分表示强调,如果把
"It is (was)...that "去掉,该句应该意思完整,不缺任何句子成分:
例句：
It was Mike and Mary who helped the old man several days ago .
2）强调部分为疑问词时:
例句：
Who was it that wanted to see me just now.
3）强调部分为 " not ... until " 句型:
例句：
It was not until late in the evening _____ her husband arrived home .
A. which B. when C. that D. how
4）复合句中的强调句型
例句：
I can't quite remember when it was that you started doing the work .
It was in the factory where he once worked that he met his lost brother.
练习：
1. 32.It was 80 years before Christopher Columbus crossed the Atlantic______ Zheng sailed to East Africa
A. when
B. that
C. after
D. since(2017重庆)
2. It was not until I came here _____I realized this place was famous for not only its beauty but also its weather.
(2017 湖南)
A. who
B. that
C. where
D. before
3. It was along the Mississippi River ____ Mark Twain spent much of his childhood.
A. how
B. which
C. that
D. where
4. Where did you get to know her?
It was on the farm _______ we worked.
A. that
B. there
C. which
D. where
5. Was it _____ he was seriously ill that he didn't come to school yesterday .
A. although B. that C. because D. since
6. It was only when I reread his poems recently _____ I began to appreciate their beauty .
A. until B. that C. then D. so
7. It was the training _____ he had as a young man _____ made him such a good engineer.
A. what ; that B. that ; what C. that ; which D. which : that
8. I can't quite remember _____ you started doing the work .
A. that it was when B. when it was that C. when was it that D. that was it when would rather