關於比較結構的省略的問題

請教1下關於比較結構的省略的問題。不是很清楚什麽時候比較從句的主語， verb ,情態詞， 助動詞省略的規則。

有時候用do ， 有時候又省略。。。。很不了解。

hoping someone can help clarify this part....thanks a lot !!!!!!

In its most recent approach, the comet cormmeelin passed the earth at about the same distance and in about tthe same position, some 25 degrees above the horizon , that Halley's comet will pass the next time it appears.

a. that Halley's comet will pass

b.that Halley's comet is to be passing

c.as Hally's comet

d. as will Halley's commet

e. as Halley's comet will do

answer is d ...

but in this question , the main sentence does not have any 情态动词或者助动词. I think the answer E is not wrong, but it says that Do has to be omitted.... please explain why?

thanks a lot ...

honeybebe，这是我的疏忽，因为LZMM问什么时候省略这些东东，我也没仔细看题。刚巧做题的时候碰到这题了，这道题跟省略还不是一回事叫我感觉，毕竟后面明确给出时间标志，the next time it appears，明确指出了时态应当采用将来时，而将来时的标志助动词当然就是will了，这里必须用的，至于相同的动词pass在这里的确是多余了，所以必须省略，就算用do也不成，因为从语法的角度上将不是不对，而是多余。

ok ....謝謝了。那你的意識是說主句的謂語動詞跟從句的動詞相同時，可以省略以免重復？

55. 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
E. but at the same time introducing some 100,000 dangerous chemical pollutant, having

B: correct

C: 两个they不一致
                

D: but不能起到引导状语从句省略的作用，应该改成introduced

E: 同上
                

在問問爲什麽 a 中的they 不一樣。。沒有看出來。。。不是代methods 嗎？

我覺得a 不錯阿。。。。

在問問爲什麽 a 中的they 不一樣。。沒有看出來。。。不是代methods 嗎？

我覺得a 不錯阿。。。。

40. To meet the rising marketing demand for fish and seafood, suppliers are growing fish twice as fast as their natural growth rate, cutting their feed allotment by nearly half and raising them on special diets.

A. their natural growth rate, cutting their feed allotment

B. their natural growth rate, their feed allotment cut

C. growing them naturally, cutting their feed allotment

D. they grow naturally, cutting their feed allotment

E. they grow naturally, with their feed allotment cut

A: as fast as 要和前面对称，rate不和前面对称

B: 同上；their feed … and raising 不对称

C: growing them naturally和前面不对称

D: correct

E: with … and raising 不对称

在問問，比如這道題，答案是d， 但是，d ，沒有省略subject, the supplier. but grow is the verb vs. the growing? i am kinda confused....