[求助]OG187

187. In one of the bloodiest battles of the Civil War, fought at Sharpsburg, Maryland, on September 17, 1862, four times as many Americans were killed as would later be killed on the beaches of Normandy during D-Day. (A) Americans were killed as (B) Americans were killed than (C) Americans were killed than those who (D) more Americans were killed as there

(E) more Americans were killed as those who Choice A, the best answer, is the only option that accurately expresses the comparison by using the idiomatic form as many... as. In B and C, as many ... than is unidiomatic, and in C and E, those who is a wordy intrusion. In D and E, more is redundant because the phrase four times as many in the original sentence conveys the idea of more.这里的as many as第二个as后面直接跟了一个句子，请问这里的as是什么词性？什么用法？