Was it yesterday that he found my pen in the classroom?

　　是昨天他在教室里找到了我的钢笔吗？

　　(2)特殊疑问式：特殊疑问词＋ is/was ＋ it ＋ that ＋句子的其他部分(陈述语序)?

　　Who was it that won the award?

　　到底是谁赢得了那个奖项？

　　How is it that you will go to visit her tomorrow?

　　明天你怎么去看她呢？

　　(3)not ... until的强调句式：It is/was not until ... that ＋句子的其他部分(肯定式，且须用陈述语序)，此时not until不能分开。

　　It was not until it stopped completely that we got off the bus.

　　直到车停稳我们才下车。

　　[名师点津]　

　　(1)区分下面两句：

　　It was 7 o'clock when he came back. (it指时间)

　　他回来时7点钟了。

　　It was at 7 o'clock that he came back. (强调句，强调at 7 o'clock)

　　他是7点钟回来的。

　　(2)because可以用于强调句式，而since, as或why则不能。

　　It was because the water had risen that they could not cross the river. (不用as或since)

　　正是由于水涨了，他们没有渡过河去。

　　[即时演练2]

　　(1)单句语法填空

　　①(2015·重庆高考改编)Bach died in 1750, but it was not until the early 19th century that his musical gift was fully recognized.

　　②(四川高考改编)Was it because Jack came late for school that Mr Smith got angry?

　　(2)单句改错

③It was until I got off the bus that I didn't realize it.