Itis(was)被强调部分+that(who)+句子其他部分。
此结构强调的成分仅限于主语，宾语和状语。
强调句的连词只有两个，that和who。当强调的部分是人，且为句子的主语时，才用"who"，其余用that。
原句：Myfatherdidtheexperimentinthelabyesterdayevening.
强调主语：Itwasmyfatherwhodidtheexperimentinthelabyesterdayevening.
强调宾语：Itwastheexperimentthatmyfatherdidinthelabyesterdayevening.
强调时间：Itwasyesterdayeveningthatmyfatherdidtheexperimentinthelab.(注意不用when)
强调地点：Itwasinthelabthatmyfatherdidtheexperimentyesterdayevening.