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。
例如：All the members held a meeting in the room yesterday.
（强调a meeting ）It was a meeting that all the students held in the room yesterday.
（强调in the room ）It was in the room that all the students held a meeting yesterday.
（强调yesterday）It was yesterday that all the students held a meeting in the room.
It 作形式主语代替主语从句，主要是为了平衡句子结构，它是形式的主语而不是主语从句。主语从句的连词保持不变。它指向的强调句强调句子的一部分，不管强调的是什么，它都可以用作连接词。
主语从句：It is +形容词/名词/某些动词ed + that 从句。
扩展资料：
主语从句，即在复杂句中充当主语成分的句子，例如"That he finished writing the composition in such a short time surprised us all"，他在很短的时间内写完作文让我们都很惊讶。
此复合句主要描述的是某事让我们惊讶，某事就是该复合句的主语，因此“That he finished writing the composition in such a short time”便是该复合句的主语从句。
主语从句的时态不受主句时态的影响和限制
例如：
（1）That he finished writing the composition in such a short time surprised us all.
他在如此短的时间内写完作文使我们十分惊讶。
（2）Whether we will go for an outing tomorrow remains unknown.
我们明天是否会去郊游仍旧未知。
（3）Who will be our monitor hasn't been decided yet.
现在还没有决定谁会成为我们的班长。
（4）Whom we must study for is a question of great importance.
“我们为谁而学习”是个很重要的问题。
（5）What caused the accident remains unknown.
事故的起因是未知的。
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。
拓展资料
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.
本回答被网友采纳其实结构相似但不相同,形似而神散,
It is + 形容词、动词的现在分词/过去分词 + 主语从句
It is important that teachers respect their students.
It is believed that dogs know men by smell.
It is interesting that nobody knew it.
It is (was)+ 名词、代词、介词短语 + that + 句子
I saw a man naked running in Quancheng Square last night.
It was I that saw a man naked running in Quancheng Square last night.
It was a man naked that I saw running in Quancheng Square last night.
It was in Quancheng Square that saw a man naked running last night.
It was last night that I saw running in Quancheng Square.本回答被提问者采纳
(1) It is Li Lei’s brother that you met in the street yesterday. 你昨天在街上所见到的就是李蕾的兄弟.
本句若将It is 及 that同时省去为：You met Li Lei’s brother in the street yesterday. 句子同样成立,因此前面的句子是强调句型.
(2) It is exciting that we have succeeded in sending up Shenzhou V. 我们成功地发射了神舟五号这件事情真令人兴奋.
本句若将It is 及 that同时省去为：We have succeeded exciting in sending up Shenzhou V. 显然句子错误,因此,前面句子不是强调句型,而是主语从句.