强调结构是：It +is/was+被强调成分+that+句子的剩余部分。如果我们要强调一个句子的某个部分时，就将要强调的那个部分放在it is/was与that之间，而句子的其余部分原封不动地直接放在that之后。此结构可强调除谓语动词外的各种成分。
It was he that saw Mr. Wang on TV yesterday. 是他在电视上看到了王先生。
It was Mr. Wang that he saw on TV yesterday. 他昨天在电视上看到的是王先生。
It is green that he has pained the door. 他把门漆成绿色了。
It is a doctor that he has become. 他已成为一名教师了。
It was on TV that he saw Mr. Wang yesterday. 他昨天是在电视上看到王先生的。
It was yesterday that he saw Mr. Wang on TV. 是昨天他在电视看到王先生。
It was by bike that we went to the park. 我们是骑自行车去公园的。
It was what he said that surprised me. 是他讲的话让我吃谅。
It is because the book is so useful for my work that I bought it. 正因为这本书对我很有用，我才买它。
It was just as he ordered that she acted. 她正是照他吩咐的去做的。
It was not until 12 o’clock that he went to bed. 直到12点他才睡。(比较原句：He didn’t go to bed until 12 o’clock. )
It was not until his father came back home that he went to bed. 直到他父亲回到家里他才睡。
(比较原句：He didn’t go to bed until his father came back home.)
It was playing computer games that cost the boy a lot of money.
It was to get my brakes repaired that I brought my car in, not to get the engine replaced!