求助语法题！

wyfish

Scientists have dated sharp-edged flakes of store 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 agao, pushing back by more than 150,000 years the earliest date when it is known that humans made store tools.

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



答案给的是E。实在是想不出来，请各位NN帮忙解答。。。。

salasbond

先提炼主干，

puching date back .....  划线部分是修饰date的，所以找一个可以正确修饰的就好

a， 有2错误，1，it is known that 是wordy, 2, 时态 it is 和后面的made冲突
b，同a一样的2错误
c，are know to be 应该是known
d, 不能用 that，应该用when，或者at which，to be making，应该是make
所以选e，

wyfish

C选项是我打错了，是Known,不是know。这样怎样排除C呢？

记得date后面的修饰语最佳的是when,所以选了A，如果用OF,就是一种“限定”。

非常感谢！

salasbond

出现时间后面如果有从句，做好是用when或者at which，因为when=at which。
如果具体的说，C选项还有错误
1. to be making
2.时态，不应该用现在时，应该用过去时

关于e，虽然这种表述比较拗口，但是它是唯一没有语法错误的。 of 是限定时间，也就是 date of humans，可以理解为人类出现的时间，后面是限定人的，什么样的人，是被知道可以制造store tools的人

wyfish

非常感谢！！