请教：新prep-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.

B. temperatures so low

C. as low temperatures

D. as few

E. as little

答案是A。 选项C为什么错？

At是介词，后面要求跟名词

所以选A不选C

as...as 中间有加N的例子啊，如下：补充题78

78.   Although many Whites, noting the presence of some Blacks in the middle class, think that the time for enforcing civil rights measures is past, Blacks generally are aware that average-income and unemployment figures show as wide a radical discrepancy as ever.

as adj.  a  N. as...(注意：这个名词应带有不定冠词)

但是都没有看到过N是复数的情况。

as...as结构有强调形容词和副词的作用吧，所以总是只夹形容词或副词，或者也是先出形容词再补名词的。

但是还是没有明确的解释。期盼NN来解答。