prep2-164和prep2-9 请教as...as的用法

tangdream

164.  
Mixed with an equal part of water, ethylene glycol, a compound commonly used as an automotive antifreeze, is effective at temperatures as low as –30 degrees Fahrenheit.
A. temperatures as low
B. temperatures so low
C. as low temperatures
D. as few
E. as little
答案：a   
答案没有问题，问题是c,大家的解释是 as..as 中间一般是用adj或者是adv, 不会用 adj+n的形式
问题是下面这题
9.   

The Environmental Protection Agency frequently puts mandatory controls on toxic substances that present as little risk as one in a million chances to cause cancer.

(A) as little risk as one in a million chances to cause
(B) as little risk as one chance in a million of causing
(C) as little risk as one chance in a million that it will cause
(D) a risk as little as one chance in a million for causing
(E) a risk as little as one chance in a million for it to cause
答案b, 这个明显是肯定了as+adj+n+as的结构

这个as..as 中间的用法？as+adj+n+as的结构 是对的？还是这题主要考虑到risk of doing的用法才选的b?
谢谢各位

tomrchu

as adj+n as是可以的

tangdream

请教LZ，那164题的c该如何解释呢？

小萧笑

as...as的比较结构，确实比较困惑。我有一下想法，一起讨论。

1， as...as第一个as是一个adv，第二个as是一个模糊的介于 prep-conj-relative

pronoun之间的词。

prep + adv是错的: prep2-164不能选C。

2. as....as之间是可以加 adj+noun的，不过好像只限于几种形式：张振邦说的：(

请大家补充）

as+不定冠词+单数可数+as   I haven't seen as old a car as this for years.

as+零冠词+不可数名词+as   好像可以对应 prep2-9,不确定，请指正。

as+零冠词+复数可数名词+as  I don't smoke as expenesive cigarettes as

those. 好像可以对应 prep2-164

可以看到，上面的形式都是    对冠词和名词的可数性作要求，没说不能加形容词。

3. prep2-9，

我觉得实在 比较 parrelism以及idiom，

rike of

chance to/of

考虑到平行，还是都用 of吧，所以选C。

另外我觉得如果 D和E改成  a risk as little as one chance in a million of

causing 似乎也就对了。

一家直言，请大家指正。 我对 as...as的用法，理解的也不透彻。

oumengling

同意  如果 D和E改成  a risk as little as one chance in a million of

causing 似乎也就对了
这里的比较对象 risk 和 one chance in a million,
as...as 结构要求比较对等，看来 GMAT 认可这两种结构
 n.1 + as + adj. + as + n.2 (n1, n2 两个比较对象)
as + adj. + n. 1 + as + n.2

tangdream

严重感谢各位大nn,讲的非常清楚，完全明白。
再次感谢