(2)一般疑问句形式: Is/Was it+被强调部分+that/who+其他?
(2014·四川高考单项填空)Was it because Jack came late for school that Mr. Smith got angry?
是因为杰克上学迟到使史密斯先生生气的吗?
(3)特殊疑问句形式: 特殊疑问词+is/was it+that+其他?
When was it that he made up his mind to take this course? 他是什么时候决定选修这门课程的?