The question that puzzled them is ______ they can get rid of the air pollution in the area

题目

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．what is it D．how it is that
①答案为D为什么B不可以,选D的原因
②这句话为什么是表语从句而不是同位语从句
谢谢!

答案

答案为D三个句子两连词够了,The question is...;that puzzled them和they can get rid of the air pollution in the area共三句,that为一连词,如果B项就多个连词,而D项又加入强调句it is这句就需要三连词了.表语从句...