来源：加拿大3.5分直营网 时间：2021-02-22 18:12:49
(1)用It is / was…that / who…句型表示强调。
被强调的部分(通常是句子的主语、状语、宾语或宾语补足语)放在is / was的后面，如被强调的是人，则后面可用who，whom等代替。
It was an old friend that / who he met in the park yesterday.
(2)not … until …句型的强调句
句型为：It is / was not until + 被强调部分 + that + 其他部分。例：
普通句：He didn’t go to bed until/ till his wife came back.
强调句：It was not until his wife came back that he went to bed.
注意：此句型只用until，不用till。但如果不是强调句型，till，until可通用，因为句型中It is/ was not… 已经是否定句了，that后面的从句要用肯定句，切勿再用否定句了。
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 / does或did。
Do sit down. 请坐。
He did write to you last week. 上周他确实给你写了信。
Do be careful when you cross the street. 过马路时，务必(千万)要小心啊!
I came home late because it was raining hard.
It was because it was raining hard that I came home late.
What you said really made us sad.
It was what you said that really made us sad.
(1) It is he who/ that often helps me with my English.
(2) It is on the hillside that we plant trees every year.
(3) It was because of bad weather that the football match had to be put off.
分析：去掉It is/ was... that/ who 句子后结构仍然完整，句意仍明确，都是强调句。
(4) It was 9 o’clock when we came back.
(5) It was 3 hours since we had come back.
分析：在上面例句中若去掉It was... when / before / since等后，句子结构就不完整，而且强调句型的后半句只能由that/who引导，所以不是强调句。
① It was him that / who / whom I met in the street yesterday.
② It was I who / that made that decision.
It was on Oct 1st, 1949 that People’s Republic of China was founded.
(6)not… until 结构的强调：
强调“not…until”引导的时间状语时，要用“it is/was not until…that…”结构，that后面的句子要用肯定式，且须用陈述句语序。例：
We did not get off the bus until it stopped.
It was not until it stopped that we got off the bus.
It was playing computer games _____ cost the boy plenty of time _____ he ought to have spent doing his homework.
A. that; that B. which; that C. which; when D. that; when
【答案】A。解析：考查强调句型和定语从句。It is/was被强调成分that/who其它成分;这是强调句型的基本结构。强调句型最大的特点就是把it is/was…that/who去掉，句子仍然成立。第一空强调playing computer games.第二空是定语从句，that指代先行词plenty of time作为spend的宾语。故选A。