最简单的方法是将it is\was及that去掉，并且剩余的部分组织起来，句子仍然能够组成完整的表达，并且成立，那么即为强调句，如若不能，否则不是强调句。
举例说明：
All the members held a meeting in the club yesterday.
（强调all the members） It was all the members that held a meeting in the club yesterday.
（强调a meeting ）It was a meeting that all the members held in the club yesterday.
（强调in the club ）It was in the club that all the members held a meeting yesterday.
（强调yesterday）It was yesterday that all the members held a meeting in the club.
It 作形式主语代替主语从句，主要是为了平衡句子结构，主语从句的连接词没有变化。而it引导的强调句则是对句子某一部分进行强调，无论强调的是什么成分，都可用连词that。被强调部分指人是也可用who/whom。
主语从句：It is +形容词/名词/某些动词ed + that 从句。
It 作形式主语和it引导强调句的比较
It 作形式主语代替主语从句，主要是为了平衡句子结构，主语从句的连接词没有变化。而it引导的强调句则是对句子某一部分进行强调，无论强调的是什么成分，都可用连词that。被强调部分指人是也可用who/whom。例如：
It is a pity that you didn'tgo to see the film.
It doesn't interest mewhether you succeed or not.
It is in the morning thatthe murder took place.
It is John that broke thewindow.