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 at which it is known that humans had made stone tools.
语法 Sentence Correction-1762
标记
正确的用户笔记
camellia00738 2015-10-03 17:07:31
用形式主语+is known+主语从句累赘，不如are known to have made简洁；主语从句的时态错误，用过去完成时需要句子逻辑上明确表明make stone tools发生在过去的过去，即有一个时间点的对比。 when后面直接跟了个it is。。。 说的意思好像是把知道这个事实的日期往前推了 原句倒过来正常顺序是pushing the earliest date at which。。。back by more than 150,000 years
liqijie3242656 2014-08-01 14:49:52
时态错误，没有明星的过去完成时的标志词表示动作发生在过去的过去
huqiao1993 2014-09-06 17:06:37
at which (it is known that.. ) 感觉是known这个行为的时间被push back了 实际上是humans make .. 的时间被push back
Sparrow_7 2016-05-25 22:37:24
had made错误，没有需要用到过去完成时
lyf0420 2015-12-02 12:07:18
句子意思--at which和when都是ok的,但是AB的意思都错 date when it is known that--等于 that... is known at the date...逻辑错误
calewu 2015-09-05 13:07:11
首先，it is结构比较啰嗦，其次，时态不对，慎重使用过去完成时。
