prep 一道关于臭氧的题目~

sunyuwei

Ozone reaches high concentrations twelve miles above Earth, where it has long appeared that it was immune from human influence; we have now realized, though, that emissions of industrial chlorofluorocarbons deplete the ozone layer.

A) has long appeared that it was immune from

B) has long appeared to have been immune from

C) has long appeared as being immune to

D) had long appeared immune to

E) had long appeared that it was immune to

一下是prep给的解释，我觉得很多点我是不能认同的，大家看看给点意见呗~

A: appeared that用法不对

B: appear to have been immune = appear immune

C: appear as being 不对

D: correct, appear 直接加形容词最简洁

E: appear that 不对

注意：

1、 appear用法，appear to do; appear adj.这里的appear 作的是系动词的用法吧？用的应该是appear adj

2、 注意正确答案的时态用法，很可能ABCDE 五个选项的时态都是可以成立的，错误都在后面我认为这里应该用的是过去完成时因为we have now realized, though, that emissions of industrial chlorofluorocarbons deplete the ozone layer.表示从过去的一定时点到现在都是realized 这个想法，那么appear 应该是发生在过去的过去的

3、 Immune from 和immune to 都对，GMAT不考介词用法真的吗？难道不是immune to 表示免疫，immune from表示免除？

sunyuwei

顶。。。。。。。。

sunyuwei

顶，，，，，，，，，