There is a new problem involved in the popularity of private cars __________ roa

题型：不详难度：来源：

There is a new problem involved in the popularity of private cars __________ road conditions require __________.

A．that ... improving	B．which...to be improved
C．where ...improving	D．when...improving

答案

A

解析

考查同位语从句和固定搭配。involved in the popularity of private cars是problem的后置定语，__________ road conditions require __________是problem的同位语从句，讲的是problem的具体内容，且同位语从句意完整，用that引导；某事需要被做，可以用require to do或require to be done 结构。所以选A。