og12-27

qiuhua01234567

suri总结得真好，我来补充下，Ron大神说过这个idiom的问题
表示某个历史时间的搭配：
estimated to be   OG12 #27
dated at              OG12 #140
不能混淆。GMAT对此要求得很死。

不过以下出现在正确句子中，所以是acceptable的：
"estimated at minus 230 degrees Farenheit"

estimate的固定用法：
estimate (that)  （不需加原V）
estimate + N + to be N(adj)  
estimate + N + at + 价格等数量词  （估价）（除此概念以外优先用estimated to be表达）
如：40 to 44 million years是时间概念，要用estimated to be 40 to 44 million years old.

-- by 会员 Suri在奋斗 (2012/3/2 23:18:14)

-- by 会员 babybearmm (2012/3/3 11:42:36)

多谢哈。。

bank11

a primate jawbone（that is) unearthed in Burma and （is）estimated that it is如果把它抽出来

a primate jawbone that is eatimated that it is·····
读起来肯定是ungrammatic
that····that····

-- by 会员 Suri在奋斗 (2012/3/2 23:21:43)

赞。。没有还原。。要仔细了。。

-- by 会员 qiuhua01234567 (2012/3/3 14:52:25)

a primate jawbone（that is) unearthed in Burma and （is）estimated that it is
这个还原不是很明白啊
unearthed不是可以是过去分词做后置定语修饰a primate jawbone吗？为什么一定要还原that is 呢？

superbat28

Paleontologists believe that fragments of a primate jawbone unearthed in Burma and estimated at 40 to 44 million years old provide evidence of a crucial step along the evolutionary path that led to human beings.

紫色部分是从句的主干，主谓宾，所以provide要用原型，是复数形式。
unearthed in burma and estimated.... 做后置定语，平行修饰fragments of a primate jawbone。后置定语可以算是定语从句的简洁形式。这里要不就全部补全变成 that is unearthed in Burma and that is estimated...，要不就两个that be就都省略，变成后置定语的平行。

而C中， that it is 40 to 44 million years old provides evidence of what was中的that it is破坏了平行，所以ungrammatical

qiuhua01234567

Paleontologists believe that fragments of a primate jawbone unearthed in Burma and estimated at 40 to 44 million years old provide evidence of a crucial step along the evolutionary path that led to human beings.

紫色部分是从句的主干，主谓宾，所以provide要用原型，是复数形式。
unearthed in burma and estimated.... 做后置定语，平行修饰fragments of a primate jawbone。后置定语可以算是定语从句的简洁形式。这里要不就全部补全变成 that is unearthed in Burma and that is estimated...，要不就两个that be就都省略，变成后置定语的平行。

而C中， that it is 40 to 44 million years old provides evidence of what was中的that it is破坏了平行，所以ungrammatical

-- by 会员 superbat28 (2012/3/27 19:39:17)

终于看见BAT了。。痛哭流涕。。

zhongshanlh

another good explanation~you can have a look~and just memorize the idiom,that's enough~
http://www.beatthegmat.com/paleontologists-t52335.html