扫描二维码，直接登录
题库 / OG2017V-CR-133
Which of the following most logically completes the argument?
When officials in Tannersburg released their plan to widen the city's main roads, environmentalists protested that widened roads would attract more traffic and lead to increased air pollution. In response, city officials pointed out that today's pollution-control devices are at their most effective in vehicles traveling at higher speeds and that widening roads would increase the average speed of traffic. However, this effect can hardly be expected to offset the effect pointed out by environmentalists, since __________.
increases in traffic volume generally produce decreases in the average speed of traffic unless roads are widened
several of the roads that are slated for widening will have to be closed temporarily while construction is underway
most of the air pollution generated by urban traffic comes from vehicles that do not have functioning pollution-control devices
the newly widened roads will not have increased traffic volume if the roads that must be used to reach them are inadequate
a vehicle traveling on a route that goes through Tannersburg will spend less time on Tannersburg's roads once the roads are widened
但其实C选项是相当充分的。这么来理解：
1、题干里面环境学家说：增加拓宽路面，引来更多的车流，最终导致空气污染增多。（注意此处的空气污染并没有特指什么样的车导致的污染）
2、政府官员反驳：我们的路面拓宽后，车子速度增高了，那些安装了污染控制设备的车就可以让其达到更高的效率。
3、gap：增加的车流有没有安装该设备，而且空气污染是否有可能本身就不是主要来源于那些已经安装了该设备的车子。
4、C：大部分的空气污染来源于那些没有安装设备的车子。直接填补gap，而且还加了限定词most，也就是说其实安装了的车子的污染，我们也考虑了的。但是由于微乎其微，所以一旦路面拓宽，如果没安装的车子增多，那么必然污染加重。
登录 或 注册 后可以参加讨论