想要区分强调句和定语从句，首先要知道它们都是怎么来的。

强调句就是当我们想要对一句话中的某个成分进行强调的时候，我们把这个成分提前，然后套入到 it is/was …… that/who ……的句型中。

定语从句是形容词性的，所以其先行词一定是名词，因为先行词在句中做不同的成分，所以采用不同的关系词。

通过例子具体分析强调句与定语从句的区别。

(1) "It is an English book (that/ which) I bought yesterday." 这句话中的 "an English book" 是对名词 "book" 进行说明，属于定语从句。

(2) "It was the English book that I bought yesterday." 这句话是通过 "that" 对 "I bought" 这个动作进行强调，属于强调句。

(3) "It was a room where we used to have meetings." 这句话中的 "where" 对 "room" 进行说明，是定语从句。

(4) "It was in the room that we used to have meetings." 这句话是通过 "that" 对地点 "room" 进行强调，属于强调句。

(5) "It is a day when the people celebrate their victory." 这句话中的 "when" 对 "day" 进行说明，是定语从句。

(6) "It was on that day that people celebrated their victory." 这句话是通过 "that" 对时间 "on that day" 进行强调，属于强调句。