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标题: GWD21-34 [打印本页]

作者: Fadaway 时间: 2008-3-15 13:47
标题: GWD21-34

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.

when it is known that humans made
at which it is known that humans had made
at which humans are known to have made
that humans are known to be making
of humans who were known to make

答案是A ，我选了C，想问下A中it的指代，还有at which和when的区别

作者: well4eva 时间: 2008-3-15 14:36

a中的it是形式主语，指代that后面humans made...整句话。

at which指某个点

when指某个时间段

作者: Fadaway 时间: 2008-3-15 21:40
多谢，问下为何这里不能用at which?

作者: weidehou 时间: 2008-3-16 23:13
小白语法里说date 与 when 是固定搭配

作者: wangming 时间: 2009-8-15 14:24
我觉得A是对的，C,D,E都是被动语态，主动优于被动啊，B的时态不对。大家觉得呢？

作者: wangming 时间: 2009-8-16 07:52
有哪位牛人帮忙解答一下吧

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