Question

Now people have come to realize ________ harmful pollution is.

A．that what

B．it

C．that how

D．how

Answer 1

D

试题分析：句意：现在人们逐渐的认识到污染多么的有害。在宾语从句中连接词不能同时应用，how用来修饰形容词的程度，故选D。