新prep2-223

223.
                (33083-!-item-!-188;#058&007226)     (T-4-Q16)

Humans have been damaging the environment for centuries by overcutting trees and farming too intensively, and though some protective measures, like the establishment of national forests and wildlife sanctuaries, having been taken decades ago, great increases in population and in the intensity of industrialization are causing a worldwide ecological crisis.

A. though some protective measures, like the establishment of national forests and wildlife sanctuaries, having been taken decades ago, great increases in population

B. though some protective measures, such as the establishment of national forests and wildlife sanctuaries, were taken decades ago, great increases in population

C. though some protective measures, such as establishing national forests and wildlife sanctuaries having been taken decades ago, great population increases

D. with some protective measures, like establishing national forests and wildlife sanctuaries that were taken decades ago, great increases in population

E. with some protective measures, such as the establishment of national forests and wildlife sanctuaries, having been taken decades ago, great population increases

答案是B，请大家帮忙看看，为什么C和E不对，如果选B，这个句子的句子结构是怎样的，多谢了。

C和E里面的having不对。从句里面没有动词了。

你可以单独把though后面的句子拿出来看。

some protective measures是主语，such as后面的可以不看了。B中是some measures were taken,C和E的动词呢？some measures having?

所以是B。