请教一个GWD题，不太确定题号

木木蓝

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.

 

1. as much as that which is being emitted annually by all

2. as much annually as is emitted by the

3. as much compared to what is annually emitted by all

4. that emitted annually by all

5. that emitted annually compared to the

我在b和d之前很犹豫，后来选了d,但不太明白b错在哪里？请各位大虾米指教！

benny9200

B中第二个as后面是谓语结构 所以与之前的对应部分平行 所以没有平行对象 因为之前并没有出现相似的结构 而逻辑上的平行对称应该是与分词修饰的pollutant 所以不对

一般的as...as结构都从第二个as入手就可以了

木木蓝

谢谢啦！只是觉得读上去还挺顺的。