请教几道大全中没有出现的题

1.Gas hydrates,chemical compounds of water and natural gas,are increasingly being studied for their potential to be huge reservoirs of energy, possibly causing sea floor instability,and significant contributors to global warming.

A.to be huge reservoirs of energy, possibly causing sea floor instability,and

B.to be huge reservoirs of energy, possibly causing sea floor instability,and even as

C.as huge reservoirs of energy, possibly causing sea floor instability,and

D.as huge reservoirs of energy, and the possible cause of sea floor instability,

E.as huge reservoirs of energy, as possible causes of sea floor instability,and even as(A)

答案是A，我选的是E。

我知道这道题在考平行对称。A认为energy导致了sea floor instability，但我认为，Gas hydrates也可以导致sea floor instability啊，就像E中那样。

请教。谢谢！

该打，昨天帖题时E选现漏了一个s，原题应该是causes。

2.Researchers agreed that the study of new treatments for heart attack patients was extremely important but more research was needed to determine that balloon angioplasty preceded with ultrasound was or was not any better for heart attack patients than the balloon procedure by itself.

A.more research was needed to determine that balloon angioplasty preceded with ultrasound was or was not any better for heart attack patients than

B.more research was needed for determining whether or not balloon angioplasty preceded with ultrasound is any better for heart attack patients than is

C.that more research was needed to determine whether balloon angioplasty preceded with ultrasound is any better for heart attack patients than(B)

D.that more research was needed to determine that balloon angioplasty preceded with ultrasound was any better for heart attack patients than

E.that more research was needed for determining that balloon angioplasty preceded with ultrasound is or is not any better for heart attack patients than is

答案是B，我选C。

引导宾语从句的that不是不能省吗，B怎么把它省了？

答案E我认为不对：（1）将第二个和第三个as后面的内容与其修饰的their potential相连，明显不通顺；（2）第三个as前面的even有递进的意思，而此句好像没有递进的意思；

这个问题的答案之争应该是在A和C之间，为什么A正确呢？因为potential后通常用不定式，这从字典里是查的到的；

为什么C不正确呢？我想，如果是Gas hydrates（或them）而不是their potential, 则后面跟as可能还说得过去（假如习惯用法允许）。

刚查了牛津，上面有个例子：She has artistic potential as an artist.

howardwang,你能把你查的帖出来看看吗？

谢谢

你的例子若改为She has her potential as an artist.可能就不太通顺。而且 as an artist有点修饰前面整个句子的感觉。不过，我的解释似乎有点牵强，我的体会比较难说清楚。还是将longman里的例子贴出来吧。

One of their children has the potential to be a brilliant scientist.

楼上说的满有道理咯,.但是我又想,一般宾语从句后面两个并列的THAT好象都是用AND连接的,那为什么不能说AND THAT不重复呢?另外这里不用BUT是不是一前面少了逗号??困惑中......!@_@