prep08-part1-256. (T-4-Q1 TS-7-41)--首次在逻辑专区开贴，求各位照顾新人..m(_ _)m..thx a ton

泾渭不凡

T.T..亲爱的斑斑们，饭饭知道这是道SC题目，但是饭饭是有一点“逻辑含义错误点”被困住，来逻辑区跪求大牛的~~所以..求求斑斑们表把饭饭的帖子搬运到SC区...求求咯...

prep08-part1-256. (T-4-Q1 TS-7-41)
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
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 be making      
E. of humans who were known to make
A. 关系代词用when和at which都是可以的；此选项表达的意思是A fact is known at the earliest date，逻辑含义错误。
C. Correct；the earliest date at which humans are known to have made stone tools.=humans are known to have made stone tools at that date (the earliest date) – AlienX.

问题：“此选项表达的意思是A fact is known at the earliest date，逻辑含义错误。”为什么错了？？？

求各位NN们指教哇~~~~~~m(_ _)m...............NN们下凡吧.........

泾渭不凡

唔。。。我是不是应该放在阅读区更合适些。。。貌似是句子分析哎。。。
o(╯□╰)oo(╯□╰)o。。。。可是貌似这里的NN们阅读能力都很强的。。。。
帮帮吧。。。小女纸感激不尽。。啊。。。。

泾渭不凡

不对。。。貌似还是需要回到语法区哎。。o(╯□╰)o哦。。
各位见笑咯。。。。。。饭饭回语法区开贴咯。。。各位加油。。。

弱弱：不过，会的懂的愿意帮助饭饭的牛牛们。。。饭饭m(_ _)m求指教啊。。。。

Suri在奋斗

饭饭，我这样想的，你看看
be known to have done sth  里面的 have done 的动作是发生在known 之前的
而 be known to do sth 发生在之后 就无需用完成时态去强调
at which humans are known to have made
人们在被知道前，在几千年前就开始用石质工具了，所以c项的时间和逻辑意思更为明确
而a的话首先是有点awkawrd
而且时间关系表示的并不明确

期待nn来~~

Suri在奋斗

http://forum.chasedream.com/GMAT_SC/thread-91380-1-1.html
找到一个关于
to have done的帖子~~(*^__^*) 嘻嘻……

babybearmm

T.T..亲爱的斑斑们，饭饭知道这是道SC题目，但是饭饭是有一点“逻辑含义错误点”被困住，来逻辑区跪求大牛的~~所以..求求斑斑们表把饭饭的帖子搬运到SC区...求求咯...

prep08-part1-256. (T-4-Q1 TS-7-41)
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
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 be making      
E. of humans who were known to make
A. 关系代词用when和at which都是可以的；此选项表达的意思是A fact is known at the earliest date，逻辑含义错误。
C. Correct；the earliest date at which humans are known to have made stone tools.=humans are known to have made stone tools at that date (the earliest date) – AlienX.

问题：“此选项表达的意思是A fact is known at the earliest date，逻辑含义错误。”为什么错了？？？

求各位NN们指教哇~~~~~~m(_ _)m...............NN们下凡吧.........

-- by 会员 泾渭不凡 (2012/4/11 16:36:01)

prep笔记这解释很切中要害：
(A) the date when it is known that ...
For example, I would say
The date when it is known that genetic mutation causes cancer is some time in the 1980s.
I mean: In 1980s, scientists made a discovery that genetic mutation causes cancer.  In other word, "some time in the 1980s" is the date for the discovery itself.
(C) the date at which humans are known to have made
The logic here is correct: we are interested in the date at which humans made stone tools, not interested in the date of scientific discovery.

以上算回答饭饭首贴的疑问。suri的解释和链接很赞，谢谢~

babybearmm

关于"known to have made"，我刚回了一个贴子，摘过来
http://forum.chasedream.com/GMAT_SC/thread-701671-1-1.html
看这个例子里: Pollock was known to have swung his paint back and forth like a pendulum


比如我随便摘一段Nature News. 咱结合句意逻辑，仔细捉摸一下所有的verb tense，都是很有讲究的啊！每个verb tense都可以echo一道GMAT SC题目。

http://forum.chasedream.com/GMAT_RC/thread-700690-1-1.html
Pollock was known to have swung his paint back and forth like a pendulum, using a can on the end of a string with a hole punched in it. Researchers have found that if a swinging pendulum is hit with a hammer at just the right frequency (slightly less than the natural rhythm of the pendulum), its motion becomes chaotic and the paint traces out very convincing 'fake Pollocks'. The artist had no idea of fractals or chaotic motion.

考点可以有：
各种verb tenses: "dinosaurs appear to have been ..."; "IF... THEN..."句型； "researchers have found ..."
that-clause
comma + v-ing
比较: "frequency less than ..."; AS vs. LIKE
parallelism
....

泾渭不凡

谢谢Suri和baby姐姐哇~~~~~还是乃们对萌宠好哇~~~~估计其他的伦就看饭饭在这发完贴之后自我纠结着觉得挺好玩的咯。。。

饭饭现在仔细看哇~~~谢谢谢谢！！！

Roxas605