▲as against 是一个成语介词，在意思上相当于 in contrast with（与……相比较；与……相对照）。又如：

Over 50% ofdivorced men regretted their divorce, as against 25% of women. 离婚男性中有50%以上后悔离婚，与此相对，女性只有25%。

▲英语介词根据其构成方式可以分为以下三类：

1.简单介词，如 about, across, after,against, along, among, at, on, in, from 等；

2.合成介词，如 alongside, inside, into,onto, outside, throughout, upon, within, without 等；

3.成语介词，如 according to, because of, bymeans of, for the purpose of, in addition to 等。

▲类似 as against 的成语介词有 as for, as to 等，它们也是两个介组成的。