It+be.。.that(who) 。..这一强调结构，这种强调结构用来突出强调句子的某一部分。该结构中的it (the emphatic it)，无词汇意义，只用于改变句子的结构，使某一部分得以被强调。要正确使用这一结构应注意以下十个方面的问题：
例如： It was my sister who first had the idea to cycle along the Mekong River from
where it begins to where it ends.(强调主语)
It was in Greece that Olympic competitions firstly started.(强调状语)
例： It was because of bad weather that the football match bad to be put off.
It was last year at the Olympics that Liu Xiang got the medal for hurdling race.是去年在奥运会上刘翔赢得了跨栏金牌。
例： It is Zhang Ziyi that (who) stars the film Heroes. 是章子仪主演的《英雄》这部电影。
It is him that I want to visit. 我想见的是他。
例：Mr. Green gave Mary a birthday present.→It was Mary that Mr. Green gave a birthday present to.
It was a birthday present that Mr. Green gave to Mary.
4. 如果原句是一般疑问句，强调结构用“be+it.。.that (who)。..?”形式;如果原句是特殊疑问句，则用“特殊疑问词+be+it.。.that(who) 。..?”形式。
Is it an the end of 2001 that China joined WTO?
When was it that the tsunami struck the countries around the India Ocean? 是何时海啸袭击了印度洋沿岸各国?
例： It was not until she took off her dark glasses that I realized she
was a famous film star.
6. 强调结构中的谓语动词除用be外，还可以用might be 或must have been。
例：It might be tomorrow that she will come.
It must have been an actor that came yesterday.
例： Further reading made me realize that it was hard work and determination as
well as her good nature that had got her into medical school.
例：It was not the fish but the vegetable， which grows only in Sichuan， that made the
hot dish sour and aromatic.
It was she who was lying in the corridor and the stranger who bent over her.是她躺在过道上，是那个陌生人俯视她。(此句有两个被强调部分：一是she，一是 the stranger)
It is that intensity， along with the low cost and low risk， that causes the real
danger of cyber lover.
例： It was my two sisters who knew her best.(都用过去时)
It will not be you who will have to take the blame for this.(都用将来时)对此受谴责的将不是你。