IT用法总结

leader

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GMAT语法中，代词一般不能用来指代整个句子，一般只能指代名词或者名词结构；唯一的例外是It，it在句首做形式主语可以指代后面的不定式或者主语从句，但这一般只限于it做形式主语。举两个例子如下：

38. Scientists have observed large concentrations of heavy-metal deposits in the upper twenty centimeters of Baltic Sea sediments, which are consistent with the growth of industrial activity there.

(A)  Baltic Sea sediments, which are consistent with the growth of industrial activity there

(B)  Baltic Sea sediments, where the growth of industrial activity is consistent with these findings

(C)  Baltic Sea sediments, findings consistent with its growth of industrial activity

(D)  sediments from the Baltic Sea, findings consistent with the growth of industrial activity in the area

(E)   sediments from the Baltic Sea, consistent with the growth of industrial activity there

In A and B the words which and where appear to refer to sediments, and in E it is not clear what consistent describes.

在这里，which就不能指代Scientists have…sediments，而要用概括性名词做同位语（D选现）来表达Scientists have…sediments与工业活动增长一致。

49. The cameras of the Voyager II spacecraft detected six small, previously unseen moons circling Uranus, which doubles to twelve the number of satellites now known as orbiting the distant planet

(A)  which doubles to twelve the number of satellites now known as orbiting

(B)   doubling to twelve the number of satellites now known to orbit

(C)    which doubles to twelve the number of satellites now known in orbit around

(D)  doubling to twelve the number of satellites now known as orbiting

(E)   which doubles to twelve the number of satellites now known that orbit

The pronoun which should be used to refer to a previously mentioned noun, not to the idea expreersonName>ssersonName>ed in an entire clause. In A, C, and E, which seems to refer to a vague concept invol­ving the detection of moons, but there is no specific noun, such as detection, to which it can refer.

OG明确说了，which不可以指代前面句子表达的意思，这种情况下只能用分词短语来代替，因此答案是B。

这样的例子在OG和大全中还有很多，限于时间关系，我就不多举了。回到楼主举的例子：

60. According to a recent poll, owning and living in a freestanding house on its own land is still a goal of a majority of young adults, like that of earlier generations.

(A)  like that of earlier generations

(B)   as that for earlier generations

(C)  just as earlier generations did

(D)  as have earlier generations

(E)   as it was of earlier generations

In E, the best choice, it refers unambiguously to the phrasal subject owning ... land

这不是句子啊，这是动名词结构啊。

我的三位考到760分以上的朋友在和我分享经验的时候都告诉我，GMAT语法是相对严格的商业英语，它的很多规则和我们平常英语语法是不一样的。在这种情况下，要想在考试中取得好成绩，最好的办法就是抠死OG。OG是唯一的权威。其他地方来的信息只能做参考。而且我个人认为在现在时间紧迫的情况下，其他语法书根本不用看，最有效的办法就是反反复复看OG。如果还有时间拿大全来练练。建议大家以后举例证明自己观点的时候，最好用OG的解释，OG的例子或者是大全里的例子。

Avantasia

leader你说的很好, 不过有一点误会了, 我没有说OG60就是指代句子啊.

就像你说的, 这里确实指代一个动名词结构, 我的意思是it可以指代的范围不仅仅局限在单词中.

livary

以下是引用薰衣紫草在2005-4-20 1:40:00的发言：

这个it确实是指代owning......因为as,like前后要完全一致. 如果一方是短语, 另一个也是, 所以it指代的不是house. 还有一个大全的例子就是讲植物呼吸的

大全81.        Although fruit can no longer grow once it is picked, it continues for some time to respire, taking in oxygen and giving off carbon dioxide, similar to the way human beings breathe.

(A) similar to the way human beings breathe

(B) similarly to human beings who are breathing

(C) just like the breathing of human beings

(D) as human beings when breathing（E）

(E) just as human beings do when they breathe

这里C就是错的, 因为它用breathing来对等respire, taking in oxygen and giving off carbon dioxide. 虽然意思上完全对, 但形式上错. 而正确答案E就用human beings do. 另外,  虽然正确答案E添加了弱语气词just, 但它还是对, 说明like,as的平行问题远远超过弱语气的添加这个effectiveness的错误.

我觉得这里两题是不一样的, 这题C错是因为the breathing 和 respire不能比较, 更何况其实句意不是要这两个比较, 而是要taking in oxygen and giving off carbon dioxide 和人类的行为比较: just as human being do.

林水监

好贴！！！很有帮助

Aurora816

总结得很详细，稍微简化一下IT的用法。
人称代词
•        是第三人称单数中性， 代表前文已提到过的一件事物
•        当说话者不清楚或无必要知道说话对象的性别时，也可用it来表示
•        IT可用来指代团体， 如Team，复合名词
•        指人Go and see who it is.
指示代词
•        IT用以代替指示代词this, that.如： What´s this? --- It´s a pen.
•        常用作没有具体意义的主语，用于表示天气、气候、温度、时间、地点、距离等意义的句子中。
•        it也常用来表示一般的笼统的情况。如：  It´s awful—I´ve got so much work I don´t know where to start.  / How is it going with you? / Take it easy.
•        it也常用于某些习惯用语中作宾语，各该习惯用语有具体意义，但it并无具体意义。如：cab it 乘车 catch it 受责，受罚 come it 尽自己分内 come it strong 做得过分 walk it 步行 make it 办成 take it out of somebody 拿某人出气
形式主语/形式宾语
•        it充当形式主语或形式宾语，本身无意义，只起一种先行引导的作用，先行词不重读。后面的真正主语或真正宾语通常是不定式结构、-ing分词结构或名词性从句。
强调句
•        以it为引导词的强调句型。它的结构形式是：It+be的一定形式+中心成分+that-/who-从句。如： It was Jane that/who called this morning.
•        强调句的时态一般应一致，即主句与从句的时态应皆用现在时，或皆用过去时，或皆用将来时。
•        有时强调句的谓语动词还可以采取复杂形式。It may have been at Christmas that John gave Mary a handbag.

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Avantasia 发表于 2005-4-19 17:12
今天看了一下大家以前关于it的讨论, 发现其中不乏重大误解, 下面是关于it的用法详解, 希望对大家有用.基本 ...

同意！