1 It is (was)⋯that(who, whom) ⋯句型：It is (was) +被强调的成分+that(who, whom) +其它成分
I am right.
It is I who(that) am right.（强调主语）
They will have a meeting tomorrow.
It is they who (that) will have a meeting tomorrow.（强调主语）
It is a meeting that they will have tomorrow. （强调宾语）
It is tomorrow that they will have a meeting.（强调时间状语）
a. 强调句中通常强调主语、宾语（包括介词宾语）、状语、短语和从句。 it 本身没有词义。
b. 强调句中的连接词一般只用who，whom（代人），that （可代物，也可代人），即使在强调时间状语从句和地点状语从句时也如此。
c. that 或who，whom 之后动词的人称和数要与它前面被强调的名词或代词一致。（即人称和数要与原句中的一致）
d. 强调句中的时态只有两种，一般现在时和一般过去时。原句谓语动词是一般过去时，过去完成时和过去进行时时，用It was⋯’其余的时态用It is⋯。
It was the way he asked that really upset me.
Was it during the Second World War that he died?（强调短语）
When was it that the Long March started?
2. 强调it 和先行词it 的判别
可用恢复原句来判别，即是把It is(was)⋯that 取消，如果剩下的仍能组成一个完整的句子，这就是强调句型，否则就不是。
It is there that accidents often happen.
There accidents often happen.
It is clear that not all boys like football.
Clear not all boys like football.
2 not⋯until⋯句型的强调句句型：It is (was) not until +被强调部分+that+其它成分
He didn’t go to bed until (till) ten o’clock.
It was not until ten o’clock that he went to bed. （强调句）
Regular radio broadcasts didn’t begin till (untill) 1920.
It was not until 1920 that regular radio broadcasts began. （强调句）
I didn’t realize she was a famous film star till (until) she took off her dark glasses.
此句型只用until，不用till 但如果不是强调句型，till，untill可通用。（参见左边3 个例句）
It was not until she took off her dark glasses that I realized
she was a famous film star.（强调句）
因为句型中It(was) is not⋯已经是否定句了，that 后面的从句要
Li Ming didn’t watch TV till(until) he finished his homework.
It was not until Li Ming finished his homework that he watched TV.
=Not until he finished his homework did Li Ming watch TV.
=Only when he finished his homework did Li Ming watch TV.
The bus will not go until (till) all the people get on it.
It is not until all the people get on it that the bus will go.
Not until all the people get on it will the bus go.
Only when all the people get on it will the bus go.
3 谓语动词的强调It is (was)⋯that⋯结构不能强调谓语，如果需要强调谓语时，用助动词do 或did。
Do sit down.
He did write to you last week.
Do be careful when you cross the street.
I did go to see you when you were in Shanghai.