强调句型的基本结构是：
It is/was+ 被强调部分(主语、宾语、宾语补足语或状语等) + that/who +句子的其余部分。
一、连接词。
一般说来，如果被强调部分是人时，用连词that或who；被强调的部分是宾语，指人时也可以用whom；如果被强调部分是物，只能用连词that。
It was John and Mike who/that saw Mary inthe street last night.
It is Mary whom/ who he often helps .
It was in the street that I met himyesterday.
二、时态。
如果原句中谓语动词使用的是现在范畴的时态(一般现在时、现在进行时、现在完成/现在完成进行时、一般将来时、将来进行时、将来完成时等)，用It is...that...。
如果原句中谓语动词为过去范畴的时态(一般过去时、过去进行时、过去完成时、过去将来时等)，则用It was...that...。
如：
Mary met an old beggar in the streetyesterday.
It was Mary who/that met an old beggar inthe street yesterday. (强调主语)
It was an old beggar whom/that Mary met inthe street yesterday. (强调宾语)
It was yesterday that Mary met an oldbeggar in the street. (强调时间状语)
It was in the street that Mary met an oldbeggar yesterday. (强调地点状语)
有时，be前可使用表示推测的情态动词。如：
It must be Peter who has let this secretout.
一定是彼得将这个秘密泄露出去的。
It might be last night that they did theirhomework.
他们也许是昨晚做完作业的。
三、强调含有not until的句子。
在强调not until句型时，not 位于until从句前，主句谓语动词作相应变化，即it is(was)+not until从句+that +其它。
It was not until he had finished the workthat he went home.
It was not until 12 o’c
lock last night that my brother came home.
四、强调句的疑问句。
强调结构的疑问形式：强调一般疑问句中的某一成分时，要在主句中用一般疑问句的顺序。例如：
Was it you that/who broke the window ?
Was it in the war that he lost his son ?
强调特殊疑问句中的疑问词，其结构模式是：“疑问词+ is/was + it +that...”。
它同感叹句的强调模式极其相似，首先将疑问句开头的部分作为强调部分，套入强调结构，然后再将其变为疑问句。例如：
1. Where were you born? →Where was itthat you were born?
2. What did you want to see? →What was itthat you wanted to see?
3. How many people are being trained forthe special work?→How many people is it that are being trained for the special work ?
五、强调句型中的主谓一致。
被强调的成分为原句的主语时，that/who之后的谓语动词应与被强调的名词或代词在人称和数方面保持一致关系，从而选用恰当的动词形式。例如：
It is you who/that are wrong.
It is I who/that am answering the question.
但是如果被强调的部分是人称代词，按理应用人称代词主格形式，但在口语或非正式文体中也可以用其宾格形式，此时that/who的谓语动词要用单数第三人称形式is或was。
例如：
It is me who is being asked the favor.
另在It is/was..., not...that...句型中，其谓语动词应与肯定部分的词保持一致关系。例如：
It is my brother, not I that studies inthat school.
It is you, not your sister that are incharge of the company.
六、感叹句的强调结构，既要体现强调句型的形式特征，又要体现感叹句的自然语序。
例如：
1. How happy he looks! →How happy itis that he looks!
2. What a clever boy he is! →What aclever boy it is that he is!
七、强调句型的鉴别方法及相似句型的辨析
强调句型极易与定语从句、名词性从句、状语从句等相关句型混淆，判断的方法是：强调句型中去掉It is/was„that剩下的部分在语法和意义上仍然是一个完整的句子。
如：
It was yesterday that I met him. 去掉句中的It was …that
该句为：Yesterday I met him.
句意和语法都非常正确，说明这是一个强调句。而其他句型则不行。
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