It is reported that PM2.5pollution is the main problem( )air pollution today.A.in B.at C.by D.with
问题描述：
It is reported that PM2.5pollution is the main problem( )air pollution today.A.in B.at C.by D.with
答
选 D.with
the problem with sth.".的问题" ,这是固定搭配
the main problem with air pollution 空气污染的主要问题
又如:The problem with video game is that they're addictive.
电子游戏机的问题在于它们会使人上瘾.
A serious problem with thermistors is that they tend to drift.
热能电阻的一个严重问题是容易漂移.保证准确率！我们考试时考的！绝对准确! 相信我!