強調句型結構

It is (was) 被強調部分+that (who) + 句子其他部分。
此結構強調的成分僅限於主語，賓語和狀語。強調句的連詞只有兩個，that和who。當強調的部分是人，且為句子的主語時，才用 "who"，其餘用that。 

原句： My father did the experiment in the lab yesterdayevening.
強調主語： Itwas my father who did the experiment in the lab yesterday evening.
強調賓語： Itwas the experiment that my father did in the lab yesterday evening. 

強調時間： Itwas yesterday evening that my father did the experiment in the lab. (注意不用when)
強調地點： Itwas in the lab that my father did the experiment yesterday evening.