E The tasks evaluating mental sharpness for which data were compiled by the study were more akin to mathematics problems than to conversation.E选项：研究给出的评估人类智力的任务更相似与数学问题而不是对话。本选项给出的是研究利用的测试智力的手段，没有理由认为这个手段可以影响人类的智力表现
3.平行，前面的是书那后面的也必须是书，排除acd
且前面是Jean Toomer's Cane，(b) is not as parallel as (e), either. since the original says "jean toomer's cane", the others should also have the form "X's Y", not "Y by X".
1.单复数问题：novels ever written by Black Americans/a Black American都可以。
借用Ron大神的例子，birds have a four-chambered heart和birds have four-chambered hearts,这两个都可以，且前者更好。套用到本题上就是，the three best novels这一类书都有一个特点，即由一个黑人作者所写。
the problem, though, is that "the intentional discarding of lens caps, packing material , fuel tanks and payload covers" IS the "littering".
so, sentences D and E are not logical.
'because of' must be followed by SOMETHING ELSE that is actually the cause of something.
'with' should be followed by a component or part of the previous observation.
In #C there's no NOUN that serves as the focus of the modifier 'resulting from...' (an adjective-type modifier). It's intended to modify the general idea that the orbits have become littered, but there's no NOUN that signifies the littering.
需要对文章的层次有深度的理解才能做对这些难度问题。
文章层层递进， 先是讲tooth pattern can help determine animal's diet. 然后讲 it has certain limitation when it comes to insect eating as only hard insect will cause tooth abrasion for baboon. 但是提到的cause indifferent tooth pattern的食物其实只有insect，所以由于物种地域分隔导致他们吃不同的食物还是有可能导致different tooth pattern.
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真正有用的前提句，即，真正能推出这个结论的句子，其实是最后一句。显然地，推理文段的最后一句给出了“接触社会”和“智力技巧”的统计关联，结论句给出了此两者的因果关系。因此，推理文段为相关因果推理。
前提：“接触社会”和“智力技巧”具有正相关关系
结论：接触社会导致了智力技巧的保持
选题方式：相关因果推理有四个评估方向，简而言之，即，答案选项要么同时提及“接触社会”和“智力技巧”，要么给智力技巧的保持另一个原因。