It is 可用于強(qiáng)調(diào)句、定語從句、主語從句等多種句型，舉例如下：

　　It is(was)that句型,It is+被強(qiáng)調(diào)成分+that+句子剩余部分（強(qiáng)調(diào)句）：

　　可以分別用來強(qiáng)調(diào)主語、賓語、地點(diǎn)狀語和時(shí)間狀語。如：

　　It was he who(that)read three books in the library yesterday.(強(qiáng)調(diào)主語)

　　是他昨天在圖書館讀了三本書。

　　It was in the library that he read three books yesterday.(強(qiáng)調(diào)地點(diǎn)狀語)

　　他昨天是在圖書館里讀了三本書。

　　It is+名詞+定語從句：

　　It was the day my grandmother was angry.

　　那一天我外婆生氣了。

　　It is +名詞/形容詞+不定式主語：

　　It做形式主語，句子真正的主語是不定式。

　　It was a pleasure to draw pictures.

　　畫畫是一種享受。