B错在哪？前面有个英吉老师说的蜜蜂蛰死人的题是什么题哦？

请比较ABC与DE 两大组，这题B的that 可以省吗？觉得D的is twice that 不对，TWICE在这里是什么词性呢？

Providing initial evidence that airport are a larger source of pollution than they were once believed to be, environmentalists in Chicago report that the total amount of pollutant emitted annually by vehicles at O'Hare International Airport is twice as much as that which is being emitted annually by all motor vehicles in the Chicago metropolitan area. as much as that which is being emitted annually by all as much annually as is emitted by the as much compared to what is annually emitted by all that emitted annually by all that emitted annually compared to the

最后留下了B和D 选了B 觉得D中不应该是和all 的vehicles