强调句型和定语从句是有区别的。
一般,强调句型的结构是:It is/was/might be + 被强调部分 + that/who +其他成分。
比如:
强调主语:
It is I who/that am right. (指人可以用who,可替换为既可指人也可指物的that)
对的是我!(或:我才是对的。)
强调宾语:
It was him who/that we met at the school gate.
我们在学校门口遇到的是他。
强调状语(你的例子就是在强调状语)
It was on Monday that I met my classmate in the railway station.
我在火车站见到同学的那天是星期一。
另外,强调句型与定语从句成分近似,比较容易混淆,这里给出解决办法:
将It + be动词 以及后面的that/who去掉,看句子是否完整:
(PS:不必关注语序,看是否为完整的“主谓宾/主谓/主系表”结构)
It was him who/that we met at the school gate.
去掉结构的句子调整顺序为:We met him at the school gate.
发现具有完整的主谓宾结构,因此是强调句型。
It was on Monday that I met my classmate in the railway station.
去掉结构,并调整语序变为:I met my classmate in the railway station.
主谓宾结构完整,故也是强调句型。
2. 如果将该句子变成定语从句,要将介词置于关系代词之前,这时才可以用相应的关系副词替换:
It was Monday on which/when I met my classmate in the railway station.
3. 但有少数情况,强调句和定语从句在形式上完全一样:
It is my teacher who/that teaches me English.
遇到这种情况,需要结合语境判断。如果没有语境,通常认为是一个强调句。