[求助]GWD-6-41 （投票啦）

sandy07627

Q41:

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.

1. when it is known that humans made
           
2. at which it is known that humans had made
           
3. at which humans are known to have made
           
4. that humans are known to be making
           
5. of humans who were known to make

Answer:  A  Or C

已经有两位高人指点过是C比较好，但是还是看看大家的意见。

如果大家不嫌麻烦的话，投票后再说说为什么吧。

谢谢。

AlienX

低人先投啦~

aeoluseros

A、humans made stone tools is known when...

C、humans are known to have made stone tools  at the date...

第一句我感觉when是修饰is known的

第二句at the date修饰made

所以还是C好...momo...

sandy07627

以下是引用aeoluseros在2008-9-3 12:54:00的发言：

A第一句我感觉when是修饰is known的

第二句at the date修饰made

所以还是C好...momo...

说的真好，我又明白了许多。