一、强调句的基本句型是it is/was+被强调的内容+that/who从句
例：John gave Mary a handbag at christmas根据上下文和语境，说话人可以通过强调句型分别强调主语、宾语、状语，使之成为信息中心。如上句可以转化为：
1.It was john that/who gave Mary a handbag at christmas.(强调主语john)
2.It was Mary that john gave a handbag (to) at christmas(强调间接宾语mary)
3.It was a handbag that john gave mary at christmas.(强调直接宾语 a handbag)
4.It was at christmas that john gave mary a handbag.(强调状语at christmas)
二、被强调的是状语或状语从句时，要用that引导句子，而不能用which，而且通常不能省略。
例：It is on the satellites of the mars that scientists have found water.
科学家是在火星上发现了水
三、被强调的是人时，引导词可以用who,也可以用that.
例：It was you that/who let out the secret to her
是你把这个秘密泄露给她的。
注意：当被强调的是主语时，代词要用主格形式。
四、被强调的不管是单数还是复数名词时，主语的be动词都用单数is或was.
对not...until 时间状语从句进行强调时，其句型是：“It is/was not until ...that从句，即not和until在强调句型中不能分开。
