As more and more cars are produced and u

问题选择题

As more and more cars are produced and used, so the _____ from their exhaust-pipes contains an even larger volume of poisonous gas.

A．exposure

B．distribution

C．expansion

D．emission

答案

答案：D

　emission散发物，发射。exposure(to)暴露于：They believe that their health problems are the result of years of exposure to fine cotton dust.(他们认为，他们的健康问题是多年来暴露于棉花粉尘所致。)expansion膨胀，扩大；Heat causes the expansion of gas.本题译文：正如汽车的生产和使用越来越多一样，汽车的排气管的散发物内所含的有毒气体量也在增加。