posed修饰谁?

hedgeforfun

6.The Audubon Society and other conservation groups, concerned over what they have perceived to be the serious threatening of the environment as posed by the policies of the government, are preparing for a major political effort.
(A) have perceived to be the serious threatening of the environment as
(B) perceived as the serious threat to the environment as
(C) perceive being the serious threat to the environment
(D) are perceiving as the serious threatening of the environment
(E) perceive as the serious threat to the environment
选e,我选了b,有什么不同?posed修饰谁?

gemj

posed修饰threat

lisashaw

E中perceive的时态对么？

gemj

现在时没问题呀，lisashaw的意思是用什么时态？