强调句型：It +is/was +被强调部分+that/who-从句
英语常用的强调结构是"It is (was)+被强调部分(主语、宾语或状语)+who (that)..."。一般说来,被强调部分指人时,用who;指事物时用that,但that也可以指人。在美国英语中指事物时常用which来代替that。
1、陈述句的强调句型
It is/ was + 被强调部分（通常是主语、宾语或状语）+ that/ who（当强调主语且主语指人）+ 其他部分。
例如：It was yesterday that he met Li Ping. 昨天他遇到了李平。
2、 一般疑问句的强调句型
It is/ was + 被强调部分（通常是主语、宾语或状语）+ that/ who（当强调主语且主语指人）+ 其他部分。同上，只是把is/ was提到it前面。
例如：Was it yesterday that he met Li Ping? 昨天他遇到了李萍吗？
3、特殊疑问句的强调句型
被强调部分（通常是疑问代词或疑问副词）+ is/ was + it + that/ who + 其他部分？
例如：When and where was it that you were born? 你何时何地出生？
4、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；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。
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.
5、谓语动词的强调
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.
例如：Do sit down. 务必请坐。Do be careful when you cross the street. 过马路时，务必（千万）要小心啊！
此种强调只用do/ does和did，没有别的形式；过去时用did，后面的谓语动词用原形。