其基本句型是：“It + is/was + 被强调的成分 + that/who + 其她成分”。It 没有实意，只起语法作用，引导被强调的部分。当被强调的是人时，可用who(m)/that, 其他情况用that。
It was I who/that met Jack yesterday. 是我昨天碰到了Jack.(强调主语)
It was Jack that/whom I met yesterday. 我昨天碰到的是Jack。(强调宾语)
It was yesterday that I met Jack. 是昨天我碰到了Jack.(强调时间状语)
这几句话复原为非强调句就是：I met Jack yesterday.
It is people, not things, that are decisive. 决定的因素是人，不是物。(强调主语)
It is because the book is very important for my present job that I bought it. 是因为这本书对我目前的工作很有用，我才买了它。(强调原因状语)
It was in the supermarket that I gave the book to him. 是在那家超市里我给了他那本书。(强调地点状语)
1.强调主语：It was John who broke the window. 是John打破了窗子。
原句：John broke the window.
It is this overpass that will be pulled down. 将被拆掉的是这个天桥。
原句：This overpass will be pulled down.
It is the people who/that are really powerful. 真正有力量的是人民。
原句：The people are really powerful.
It was at that moment that he changed his mind.是在那一刻他改变了主意。
It is every day that Professor Smith goes swimming.史密斯教授是天天去游泳。
It was not until Saturday that he began to prepare for the examination. 他直到星期六才开始为考试作准备。
注意：这句话的原句是He did not begin to prepare for the examination until Saturday. 变成强调时间状语，注意 “not” 位置的变化。
It was in the library that I met Jack yesterday.是在图书馆我昨天碰到了Jack.
原句：I met Jack in the library yesterday.
It might have been on the bus that I lost my purse.可能是在公共汽车上我丢失了钱包。
原句是：I might have lost my purse on the bus. 强调地点状语，
也可改为：It was on the bus that I might have lost my purse.
It was under the tree that I was sitting then. 当时我正坐在那棵树下。
It was Tom’s bike that she borrowed, not mine.她借的是Tom的自行车，不是我的。
It is his dog that he’s sold, not his car. 他已卖掉的是他的狗，不是车。
It was a cat that your dog was running after. 你的狗追的是只猫。4.强调宾语补足语：
It was wonderful that we considered his plan.我们认为他的计划是绝妙的。
It is Lincoln that they named the aircraft carrier.他们把那艘航母命名为林肯号。
It was captain that the team chose him. 那个队选他当的是队长。
It was white that Tom was painting the fence.汤姆当时正在把篱笆涂成白色的。
这句话的原句是： Tom was painting the fence white.
类似的结构有：color the sun red, color the tree green, paint the wall pink 等，这里，颜色作宾语补足语。
It is a fine player that we believe Jane.
It is the Buckingham Palace that the British Queen’s office building is called. 英国女王的办公大楼被称作白金汉宫。
It is Cadillac that this car is named. 这辆车被命名为卡迪拉克。
用“助动词do + 动词原形”来强调谓语动词。
You’re quite wrong?she does like you. 你错了，她真的喜欢你。
Do come in. 快进来。
用“助动词do + 动词原形”来强调谓语动词。
I work hard. → I do work hard.
She loves you. → She does love you.
My father smokes a lot. → My father does smoke a lot.
I called you in the morning.
→ I did call you in the morning.
I attended the meeting yesterday.
→ I did attend the meeting yesterday.
I handed in the paper yesterday.
→ I did hand in the paper yesterday.
He wrote a letter to me yesterday.
→ He did write a letter to me.
He came to see you yesterday.
→ He did come to see you yesterday.
That film?what do you think of it?
Asleep, then, were you?
2.用某些特殊的词来表示强调，如really, certainly, definitely, very等。在口语中，such 和so 都常用于强调句。
Thank you so much.
It was such a lovely party.
I really enjoyed it.
This is the very book that I am looking for. 我要找的就是这本书。