问题
选择题
The question that puzzled them is ____ they can get rid of the air pollution in the area.
A．how is it that
B．that how
C．that it is how
D．how it is that
答案
答案：D
题目分析:考查表语从句。此处是强调句型的特殊疑问句做表语从句，语序为：疑问词+it +is +that+被强调部分，故答案选D。句意：使他们困惑的是他们如何才能去除这个地区的空气污染。