请教一道语法考古题！大全249

大全249

Doctors still know little about how the Listeria bacterium is spread and why the disease it causes, listeriosis, afflicts some people in a contaminated area though it spares many others.

(A)though it spares
(B)where it spares
(C)despite sparing
(D)when sparing
(E)while sparing

AnsE)
請問A)為什麼不對??
好像是(A)it 和題目中it causes 的it 是指兩個不同的東西.
不過我還是不太了解..
題目也好像怪怪的 causes, afflicts 有兩個verb ??

causes 後面為什麼要有逗點??

thanks

Doctors still know little about how the Listeria bacterium is spread and why the disease
                it causes, listeriosis, afflicts some people in a contaminated area though it spares many others.

it causes -----定从修饰disease~，it指listeria bacterium

如果选A，it的逻辑主语应该是disease，但实际主语却指了bacterium，所以错~

This is the way how I see this ...

Doctors still know little about how
                the Listeria bacterium is spread and why
                the disease (which)it causes, listeriosis, afflicts some people in a contaminated area though it spares many others.

it  指 Listeria bacterium
            

the disease = listeriosis 

it 指 disease

同一個句子 it 指代不同事物 所以(A)錯

listeriosis 為appositive(同位語)  因為插入句 (which) it causes 之故 所以前後加逗號隔開

open to discuss

請問A)為什麼不對??
好像是(A)it 和題目中it causes 的it 是指兩個不同的東西.
不過我還是不太了解..
題目也好像怪怪的 causes, afflicts 有兩個verb ??

causes 後面為什麼要有逗點??

er。。。er以上问题你自己都答完了~

同一句话中，同类代词的指代必须一致：they、them、their ； it、its 否则会有歧义

why the disease it causes, listeriosis, afflicts。。。

it causes是the disease的定语从句，causes是定语从句的谓语动词；afflicts是主句宾语从句的谓语动词

我是这么看的：只看why后面，主干是 the disease afflicts some people in a contaminated area while sparing many others.

while有“而、却”的意思，从语感上讲也比较顺

另：Listeria bacterium is spread and why the disease it causes, listeriosis,

it指“listeria bacterium”,listeriosis就是前面那个disease的名字

97.   (29753-!-item-!-188;#058&003991)

Industrialization and modern methods of insect
control have improved the standard of living around the globe while at the
same time they have introduced some 100,000 dangerous chemical pollutants,
having gone virtually unregulated since they were developed more than 50
years ago.

(A) while at the same time they have introduced
some 100,000 dangerous chemical pollutants, having

(B) while at the same time introducing some
100,000 dangerous chemical pollutants that have

(C) while they have introduced some 100,000
dangerous chemical pollutants at the same time, which have

(D) but introducing some 100,000 dangerous
chemical pollutants at the same time that have  (B)

(E) but at the same time introducing some 100,000
dangerous chemical pollutants, having