问题
选择题
______we were worried about was ________they could manage to control the pollution.
A．That how
B．That whether
C．What that
D．What whether
答案
答案：D
本题考查名词性从句。What引导主语从句，从句中缺少宾语，whether引导表语从句，句意：我们所担心的是他们能否成功的控制污染。选D。