date不是应该搭配at的嘛？

Rachel76

Scientists have dated sharp-edged flakes of stone found in the fine-grained sediments of a dry riverced 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 humans are known to have made
D. that humans are known to ve making
E. of humans who were known to make
看到选项，义不容辞吧ACE排除了，没想到答案是E。。求各位大侠解答~

puqiandi

顶
召唤nn

foleygump

看了答案，然后试着去解释，还能理解E为什么是对的，而且它选项错了。但是如果一开始从中直接选出E，我肯定会做错。我可能会选B。希望大牛能帮忙呀。

Jasmine10

Parellel? " dated sharp-edged flakes of " and "the earliest date of ". I am not sure about it...

sportmann

(C) should be the correct answer.

yawgamoth86

這題就是C阿。。。

puqiandi

答案E啊

puqiandi

我后来想了好几遍觉得ABCD意思都不对，它们说的都是在那个date，human被known了会make stone tools，而事实上意思是，会make stone tools 的人的那个date。

sportmann

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 (it 形式主语，但用法有歧义，见10楼）
B. at which it is known that humans had made （同上）
C. at which humans are known to have made （date at which 正确；不定式的动作已经完成所以用 know to have made 正确）
D. that humans are known to be making (to be making在这里用法不当）
E. of humans who were known to make （date of humans 这个表达很awkard 后面最好跟一个定语从句；另外后面的known to make表示动作发生在当前，这个不正确）

zxtcomeo

a 选项it 指代that 从句 ,何以说指代不明?
这和 it is important that .....一样的! 指代不明何从谈起? 楼主这道题在哪找的? google 上搜找不到呀? it is 这种句型在这里是不是显的 awkward?  不如c 选项的那种表达简洁,而且 when 不如 at which 好,应该选c !不知道哪位牛人能给分析一下 a 选项