it在强调句中的使用

先看看这道题：

__________ these boys that played tricks on their teachers.

A. They were                        B. It were                        C. There were                        D. It was

【分析】此题应D。这是一个强调句型，其基本结构为：

It is＋被强调部分＋that(who)＋其他

该句型应注意以下几点：

1. 不管被强调部分是单数还是复数，其前一律用It is / It was，而不能用They are / There were之类的。

2. 被强调部分是指人时，被强调部分后可用that / who，被强调部分指物时，被强调部分后只能用that。

3. 被强调部分是指时间或地点时，被强调部分后通常用that，一般不用when，where之类的。

It is I who am right. 是我对。

It was you that were wrong. 是你错了。

It was in the Japan that he died. 他是死于日本。

It was yesterday that he got married. 他是昨天结婚的。

It was a computer that he bought last week. 他上个星期买的是一台电脑。

Where was it that she lived? 她是住在什么地方?

When was it that he left for Japan? 他是什么时候离开去日本的?

Who is it that teaches you English? 是谁教你们英语?.

source: http://www.yygrammar.com/Article/200907/1280.html