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标题: [求助]XDF的一道题~~~ [打印本页]

作者: heiheituzi 时间: 2009-4-1 22:35
标题: [求助]XDF的一道题~~~

Scientists have dated sharp-edged flakes of stone found in the fine-grained sediments of a dry riverbed in the Afar region of Ethiopia to between 2.52 and 2.60 million years ago, pushing back by more than 150,000 years the earliest date when it is known that humans made stone tools.

A. when it is known that humans made

B at which it is known that humans had made
C at which it is known that humans had made
D that humans are known to be making A
E of humans who were known to make

天山答案C，XDF答案E 。我觉得BC时态错，D to be doing 这个结构错，但具体为什么错不懂，只是觉得一般出现它肯定不选~~~

作者: heiheituzi 时间: 2009-4-2 22:16

UP~~~

作者: carolhide 时间: 2009-4-3 09:09
A/B/C的it作为形式主语没有指代吧，it不能指代that从句。

作者: heiheituzi 时间: 2009-4-3 21:47

it做that 从句的形式主语不行吗?

GMAT里it不是可以指代 that从句和 to do吗???

作者: xxxyyyzzz1 时间: 2009-4-5 20:16
个人觉得at which后面又有it
根据就近原则的话，which 指date，it指代什么呢？难道是指代前面发现xxx的事情么？如果是指代现在被发生的事情，后面的known that是不是说，这个事情是指人第一次制造工具？
如果it不是指代，是形式主语的话，后面没有真正的主语啊......

E中know to do的用法前几天看到个帖子，说的是如果用在表示过去的时态中，是说以前发生的事情现在被人们知道了，而以前是不知道的...OG里面也有这样的题，忘了是哪里了...

不知道说的对不对，请讨论~~~

作者: 天蝎座1107 时间: 2009-4-5 23:03

我选E

A有歧义让人以为在那个时间大家知道人类会取火

B C时态改成过去完成时没有明确时间标志的情况下无故改成过去完成时错

D to be making错

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