it is/was ...that...是一个固定句型，这是个
强调句型，可以强调除谓语以外的所有
句子成分，第一个省略号那么地方是填强调的成分，后面省略号是填句子剩下的成分(即：it is/was +被强调的成分+that+剩余部分）用这个句型的强调句把 it is/was that 去掉后依然是个完整的句子。
eg.my father went to see me off yesterday in the airport.
→it was my father that went to see me off yersterday in the airport. (对主语进行强调）
→it was in the airport that my father went to see me off yesterday.（对地点状语尽兴强调）
... 还可以对时间状语进行强调，就不写出来了。
另外：若对not.. until进行强调，则把not放到until前面
eg.it was not until she took off her dark glasses that i found she was a film star.