从高考题看“It” 用法与考点延伸(2)
2016-11-24 01:08
导读：考点（2）：Itis+V.-ed+that结构与as引导的非限制性定语从句及主语从句的区别： _____isknowntoallthatalllivingthingsmusthavefreshwatertosurvive. _____isknowntoall,alllivingthing
考点（2）：It is +V.-ed +that 结构与as引导的非限制性定语从句及主语从句的区别：
_____is known to all that all living things must have fresh water to survive.
_____ is known to all , all living things must have fresh water to survive.
_____ is known to all is that all living things must have fresh water to survive.
A. It B. As C.Which D. What
这三道题的答案依次为：A, B, D 。第一句只有一个主谓结构，主语是 all living things must have fresh water to survive, 句首的是形式主语，因而选择It; 第二句中的逗号表明两句为从属关系，由句意判断主语指代的是all living things must have fresh water to survive，定语从句中可以指代整个句子又能置于句首的关系代词只能是as; 第三句以第二个is 为分界线，之前是主语从句，之后为that引导的表语从句，分析主语从句中缺少的成分为主语，确定答案为what。
考点（3）：It用于形式宾语的常见结构：
主语+V. +it +adj./n. +to do /doing /从句…
能用于此结构的动词有：think, consider, find, believe,make, feel。因这样的动词有6个，宾语补足语有名词或形容词两种形式，真正的宾语有不定式、动名词、从句三种形式，又将这种结构称之为“6123”结构。
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4.It is the first/ second … time that +主语+现在完成时
It was the first/second… time that +主语+ 过去完成时
用上述句型表示“某人第…次做某事”，从句中的时态用完成时。
5.It 的模糊用法
(06全国I) If I can help______, I don’t like working late into the night.
A. so B. that C. it D. them
(04全国I) I like ____ in the autumn when the weather is clear and bright.
A. this B. that C. it D. one
这两道题的答案都是C。句子中的it分别用来指代working late into the night 以及when the weather is clear and bright.
It常用在一些表示喜好的动词后，指代句子或其他成分。
It 有这种用法的句型有：
I take it that … 我理解为…
I hate it when… 我讨厌…
（转载自http://zw.nseac.coM科教作文网） I don’t mind it if… 我不介意…
Please see to it that… 请务必…
You can count on/depend on it that … 你可以相信…
When it comes to … 讲到…
