疑惑：Estimated at & to be

metoo9

先上题：
1、OG13.Q30
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.
(A) at 40 to 44 million years old provide evidence of
(B) as being 40 to 44 million years old provides
evidence of
(C) that it is 40 to 44 million years old provides
evidence of what was
(D) to be 40 to 44 million years old provide
evidence of
(E) as 40 to 44 million years old provides evidence
of what was

Key
OG的解释如下：
Idiom; Agreement
The verb estimatedshould be followed by the
infinitive to be, not the preposition at—unless the
writer intends to indicate a location at which
someone made the estimate. The jawbone
fragments were estimated to be a certain age. The
plural subjectfragments requires the plural verb
provide.

2、PREP07. SC1.Q86

An international team of astronomers working at telescopes in the Canary Islands and Spain has detected at least 18 huge gas spheres estimated to have 5 to 15 times the mass of Jupiter, the solar system's largest planet.

(A)astronomers working at telescopes in the Canary Islands and Spain has detected at least 18 huge gas spheres estimated to have 5 to 15 times the mass of Jupiter

(B) astronomers working at telescopes in the Canary Islands and Spain has detected at least 18 huge gas spheres estimated to be 5 to 15 times Jupiter's mass

(C)astronomers is working at telescopes in the Canary Islands and Spain, having detected at least 18 huge gas spheres that are estimated at 5 to 15 times the mass of Jupiter

(D) astronomers, working at telescopes in the Canary Islands and Spain, and has detected at least 18 huge gas spheres estimated at 5 to 15 times the mass of Jupiter

(E) astronomers, working at telescopes in the Canary Islands and Spain, has detected at least 18 huge gas spheres they have estimated to be 5 to 15 times Jupiter's mass

Key：A
PREP解释：
习惯用法: estimate at 后常用价格等数量词,除此以外的概念优先用 estimate to

以上两题选出答案不难，只是疑惑estimated to与 estimated at的区别。

个人理解是：
第一题的estimated是V.动词，所以它的用法应该同OG所说一致。
第二题的estimated是分词，所以用法又不一样了。

不知道上述的理解是否正确，还望路过的NN指点。

除此之外，想问关于estimate to 和 estimate at的用法还有别的区别或者是需要注意的知识点吗？  

小女子先在此谢过各位大侠出手相助。

seeingyou

摘自前辈解释：
At is Preposition.
Prepositions must be followed by Nouns.
“xxx number of years old" is not a Noun.

但是关于选项B和E还有一些疑问，请大家看一下。

B) as being 40 to 44 million years old provides evidence of
E) as 40 t0 44 million years old provides evidence of what was
不看其它问题，只关注与as being和as。

E被排除我的分析如下，不知道对不对，求讨论：

OG中没提到estimated as为错误。但根据as用法应该不能对。

As要么作连词引领clause，这里明显不是。

要么作介词引领Noun or Noun Phrase，XX years old明显不是名词结构。

所以除非as还有其它用法不然应该算错。

问题在于，XX years old算什么结构，adj.?

我排除了B中as being基于以下原因：

如果as在此起介词作用，有三种可能含义，

1）Funtion

2) Equation

3) Stage

似乎哪个都不合适，所以排除。

但是，问题在于：

B的being XX years old尽管看起来很awkward，但难道不能算Noun Phrase，从而被as引导吗?

jiaoguitar

我不觉得GMAC会考同一个动词与不同介词搭配表达不同含义的考点，几乎所有的真题出现过的动词与介词搭配都是固定的。estimate to/ date at 就此记住就行了。

eb1forever

Rock samples taken from the remains of an asteroid about twice the size of the 6-mile-wide asteroid that eradicated the dinosaurs has been dated to be 3.47 billion years old and thus is evidence of the earliest known asteroid impact on Earth.
A.has been dated to be 3.47 billion years old and thus is
B.has been dated at 3.47 billion years old and thus
C.have been dated to be 3.47 billion years old and thus are
D.have been dated as being 3.47 billion years old and thus
E.have been dated at 3.47 billion years old and thus are

dated at?

jeffery2541

楼主说estimated at后常跟价格等数量词
可是Manhattan SC里idioms那一章里说
"She estimates the cost at 10 dollars"这句话是错误的，要把at改成to be

-- by 会员 MINOZ芸 (2012/7/18 21:13:41)

"She estimates the cost at 10 dollars"
这个例子里estimate变成了及物动词的用法了，是这里不一样了吧~
也就是说作及物动词用时，那个at就可以看成修饰cost的，就是宾补了，而不是直接和estimate搭配吧~

metoo9

楼主说estimated at后常跟价格等数量词
可是Manhattan SC里idioms那一章里说
"She estimates the cost at 10 dollars"这句话是错误的，要把at改成to be

-- by 会员 MINOZ芸 (2012/7/18 21:13:41)

"estimated at后常跟价格等数量词" 这个出自PREP07. SC1.Q86
我现在被to be 和at 各种弄晕了
还是按照to be 和 at 的意思来理解什么时候用哪个好了。

MINOZ芸

楼主说estimated at后常跟价格等数量词
可是Manhattan SC里idioms那一章里说
"She estimates the cost at 10 dollars"这句话是错误的，要把at改成to be

jeffery2541

estimate to be...years old/date to be...years ago/date at...years old
以上三个词组是我以前总结的关于表示预测年龄的表示方法。
刚才查了查，estimate有两种用法，一是estimate to be，另一个是estimate at，其中前者是不定式的用法，后者一般是对worth, amount, size, weight的估计时使用；我只见到这样一个例句： I estimate his age at thirty-five.是estimate at和age有关的，会发现此时estimate是及物动词的用法了，而at thirty-five是宾补。