1、prevent somebody/something (from) doing something 这里from 是可以省略的，如：Wrap eggs in paper to prevent them being damaged，来自朗文例句。所以DE的问题应该还是在aim to上，个人认为至少E的形式没有问题；
2、翻了些词典，aim 大体有三个意思，刚好aim at都适用这三种意思：（1）指向，aim a camera at me（镜头对准我），（2）针对（特定人群或事物），These ads are aimed at young people（这些广告是针对年轻人的）；（3）to plan, hope, or intend to achieve something，力求达到/旨在。显然这里的aim to和aim at 都属于第3个意思，用法分别为：aim to do sth和aim at doing sth，但有细微区别的是aim to do的动作发起人一般为人或机构，如I aim to be a millionaire by the time I'm 35 字面翻译为“力求达到”，aim at sth/doing sth动作发起方是计划、方案等事物 ，如The talks are aiming at a compromise 字面翻译为“旨在于……” 所以这里医保法案用aim at 不用aim to
一家之言，轻拍

1. 如果用名词prevention的话，整个句子的重心就变了，aim at the prevention 而不是aim at preventing ... (这件事)
2. prevent sth or prevent sb from doing sth
destroying an elderly patient变成了修饰的内容，原句的意思是防止illness destroy 老人，这里只是防止illness，这个illness会destroy老人。

楼下说得对，D有歧义，destroying……也可以作illness的定语 aim at和aim to没毛病

prevent sb./sth.（from）doing sth.
aim to do sth. 动作发起人一般为人或机构
aim at sth./ doing sth. 动作发起方为计划、方案等

引用：
1、prevent somebody/something (from) doing something 这里from 是可以省略的，如：Wrap eggs in paper to prevent them being damaged，来自朗文例句。所以DE的问题应该还是在aim to上，个人认为至少E的形式没有问题；
2、翻了些词典，aim 大体有三个意思，刚好aim at都适用这三种意思：（1）指向，aim a camera at me（镜头对准我），（2）针对（特定人群或事物），These ads are aimed at young people（这些广告是针对年轻人的）；（3）to plan, hope, or intend to achieve something，力求达到/旨在。显然这里的aim to和aim at 都属于第3个意思，用法分别为：aim to do sth和aim at doing sth，但有细微区别的是aim to do的动作发起人一般为人或机构，如I aim to be a millionaire by the time I'm 35 字面翻译为“力求达到”，aim at sth/doing sth动作发起方是计划、方案等事物 ，如The talks are aiming at a compromise 字面翻译为“旨在于……” 所以这里医保法案用aim at 不用aim to

aim to: 旨在，目标是
aim at: 针对....
不能说目标是防止xxx吧？目标应该宏大一点

prevent XXX from XXX: 阻止. 所以from 后面一边是主动语态。你不能说防止阻止A被怎么样，这逻辑不通。

Diction; Logical predication
The sentence as written is not stated clearly. For example, it is unclear what
is shaped so smoothly and perfectly; it could be either the airplanes or
the wings. Upon considering the likely intended meaning, along with a review
of the other answer choices, it seems most likely that the phrase is intended to
modify frictionless wings.
Next, we need to consider whether it makes more sense to say that the wings
are smooth or shaped smoothly. This issue can be determined only by
considering the most plausible intended meaning rather than by considering
just the grammar of the sentence. The idea of being smoothly shaped would
seem already to be part of the idea of being shaped perfectly, and therefore it
is redundant. On the other hand, having a surface that is very smooth would
be crucial in a quest to make an airplane wing frictionless; for this reason, it
makes sense to point out that the wings themselves are smooth.

A. This choice is incorrect for the reasons stated above.
B. Correct. Given the repetition of the word wings, it is clear that what
follows modifies wings and not airplanes. Describing the wings
as smooth and perfectly shaped clearly conveys what is most likely
intended.
C. In this version, note that shaped is modified. For this reason, proper
grammar requires that the adverbs smoothly and perfectly are needed
rather than the adjectives smooth and perfect. However, as discussed
previously, the intended meaning of the sentence would be better
conveyed if we used the adjective smoothto modify wings rather than the
adverb smoothly to modify shaped.
D. It is initially unclear what is being described as having been shaped in
such a smooth and perfect manner; it could be either the airplane or its

wings. Even if that were clarified, however, the sentence would be flawed:
the sentence is intended to describe the wings themselves, not
the manner in which the wings were shaped. That is, this wording could
be interpreted as referring to the nature of the wings themselves or to the
process through which they were made. This ambiguity makes the
meaning of the sentence unclear.
E. This version is very awkwardly worded, mainly because of having been.
Furthermore, this version describes the act of shaping the wings. Because
the sentence is instead meant to describe the wings themselves, this
choice is incorrect.

A我觉得一是名词prevention问题，二是一个病和很多老人不匹配的问题，所以E也有一样的问题了
CD之间问题在于D把from省略之后会有destroying修饰老人的嫌疑，这样子与句意不相符

prevent from

aim to 打算 计划 aim at 针对。。。

prevent xx from doing 避免xx做某事
aim to 目的是做什么
aim at 针对什么

be aimed at ~~~~~~~~ aim to

D选项容易引起歧义，不知是prevent catastrophic illness还是prevent a catastrophic illness destroy an elderly patient

核心词

1 prevention of ..from 冗长复杂且不准确
2preventive是预防药，医疗保险怎么能being 呢。
3语句没有问题。
4 5表达不清准。而且 to 不如at， aim to 是打算决定目的是干什么。 aim at是针对。 两者有些微区别，在这里aim at更合适。

Aim to do 和aim at 都可以，本题先通过Prevent杀掉DE, prevent sth or prevent sb from doing sth
D：destroying an elderly patient变成了修饰的内容，原句的意思是防止illness destroy 老人，这里只是防止illness，这个illness会destroy老人

Aim to do 和aim at 都可以，本题先通过Prevent杀掉DE, prevent sth or prevent sb from doing sth
D：destroying an elderly patient变成了修饰的内容，原句的意思是防止illness destroy 老人，这里只是防止illness，这个illness会destroy老人

A。prevention of 不如preventing xxx 合理
B。being 多余
C。合理表达句意
D：destroying an elderly patient变成了修饰的内容，原句的意思是防止illness destroy 老人，这里只是防止illness，这个illness会destroy老人。
E：同理改变句意。

应该是 was aimed at比 was aimed to 表意更准确

As what Ron said, 动词的名词形式重点在动作本身，而名词是和施加它的主语有关。
aim at比aim to的表意更加简洁。
prevent…from…，防止某人做某事，介词from通常可以省略。但是，在被动语态中，介词from不能省略。