第二步：語法精講
　　1. 簡介
　　(1) 一般情況用It is (was)…that (who)…，指人時，用who；指物時，用that。
　　我們分別可以強調主語、賓語、表語、時間狀語和地點狀語等。如：
　　He read three books in the library yesterday.（正常句子）
　　It was he who read three books in the library yesterday.（強調主語）
　　It was three books that he read in the library yesterday.（強調賓語）
　　It was in the library that he read three books yesterday.（強調地點狀語）
　　(2) 強調狀語或定語時，只用that，不用when、where，如：
　　It is at 5 o’clock that the train will arrive.
　　(3) 被強調的部分是主語時，注意句子的謂語動詞和被強調的主語保持一致。如：
　　It is he who is late.
　　It is they who were late.
　　(4) 一般疑問句的強調句為“Is (was) it + that…?”；特殊疑問句為：“特殊疑問詞+ is (was) +it +that…?”結構。如：
　　Was it ten years ago that his father died?（他的父親是十年前去世的嗎？）
　　When is it that you will set off?（你到底什么時候出發？）
　　(5)“not…until…”句型的強調結構為“It is not until…that…”應注意把否定詞not轉移到until前面。如：
　　I didn’t go home until the rain stopped.（直到雨停了我才回家）。
　　強調句為：It was not until the rain stopped that I went home.
　　I didn’t know the news until yesterday.（直到昨天我才知道那個消息）
　　強調句為：It was not until yesterday that I knew the news.

　　2. 四級必考套句學習
　　(1) It is the responsibility of to do sth.
　　【分析】注意，從形式上看該句子很像強調句型，而實際上并非如此，因為句中it是形式主語，動詞不定式作實際主語。
　　It is the responsibility of every citizen in our society to do his utmost to protect the environment.
　　(2) It is the , I suppose, that have\has given rise to .
　　【分析】該強調句型強調句子主語，I suppose作為插入語。這是一個很好掌握的四級長句，在作文中需要分析原因時，可以用它闡述自己的看法。
　　It is the tighter job market, I suppose, that has given rise to the increase in the number of unemployed college students in China.
　　(3) It is only when that .
　　【分析】強調句型強調when引導時間從句。
　　It is only when you nearly lose someone that you become fully conscious of how much you value him.

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