问题补充:
--- I think the environment is becoming worse and worse.
--- Yes, I really don’t know we can do about it.
A. which
B. whether
C. that
D. what
答案:
A. which
B. whether
C. that
(答案→)D. what
解析:词义辨析。Which哪一个;whether是否;that那个;what什么。句意:我认为环境变得越来越差了。——是的,我们真的不知道关于这事我们能做什么。下文宾语从句中缺少逻辑宾语。故选D。