remember, ALL of the wrong answers are COMPLETELY wrong. if you think that one of the wrong answers is just 'worse than the correct answer', then, nope—more review is in order.

if a CR problem is hard, the difficulty ALWAYS comes from the specific content/words/topic, and NEVER comes from 'logic' or 'structure'.
if you spend the time to come up with a GOOD analogy—something that may take quite a while—you may find that it becomes trivially easy to understand how the original problem works.

it is true that "evaluate" problems can generally be converted into weakening (or strengthening) problems.
generally, all that's necessary to do so is to change the "whether" into an actual yes/no.

不认识inept完全没办法做题。

The first is not context (or background) - it is a premise used to draw a conclusion. The second is not the main point of view but a contrasting point of view.

D为什么错。

一个人违反交规，警察罚他，他却指责别人错的更离谱。

in choice d, you could legitimately make a case that 'spending' could modify the entire huge clause about what insurance plans do, and is therefore ambiguous. however, that's the OA, so you've learned that this problem is ok in the eyes of the gmat people. if there's a rule that can be articulated here, it's probably something along the lines of 'participial modifier applies to nearest action'.

it should be 'includes', because the only noun that makes sense as an antecedent here is 'group'.
after all, it's the group that 'includes' its members. if you say 'hoofed mammals that today include cows, camels, ...', then the literal interpretation is that you're talking about hoofed mammals that actually contain cows, camels, and so forth as parts of their bodies! now that would be scary.

it's actually an issue of parallelism, not idiomatic usage. remember that two-part parallel constructions (such as "either ... or ...") must be exactly parallel grammatically.

there is an EXCEPTION to the principle that a pronoun must stand for an actual noun.
here is that exception:

in the construction
it is/was ADJ that...
or
it is/was ADV that...
or
it is/was ADVERB PHRASE that...
the "it" DOES NOT have to stand for an actual noun.

note that the "THAT" after the adjective/adverb/adverb phrase is absolutely necessary.

做了一万遍，还是倒在这个单复数上，好无语

In sum, although Nightingale may not have achieved all of her goals during the Crimean War, her breadth of vision and ability to realize ambitious projects have earned her an eminent place among the ranks of social pioneers.

看明白了。。The researcher found, as expected, that the computer-model stream broadened with time. ←时间越长stream越宽是客观事实。理论的争议是在粒子分布的密度。

选项D说新旧理论都同意older streams流星雨时间更长，可是conventional theories的理论明明是particles会变得更紧密increasingly dense toward the center of a meteor stream，因此时间流星雨时间会变短才对？陷入了奇怪的思考回路 求解析

But 平行标志，多方面描述同一个事物—找平行！

Any choice with a simple present tense used in this context, makes it look as though it is the routine habit of rich nations to join the downward slide toward more lax attitude.

examples: private universities have admitted more females than males --> meaning: this is an ongoing or cumulative trend, continuing into the present from some designated starting point
private universities admit more females than males --> meaning: this is a fundamental truth about the way private universities operate

mistakenly to conclude that because such advances are initiated by rural leaders and are based on traditional values and practices, they retard "real" economic development.

use fire的目的（比如说用来烧这些动物），E说明了这些动物是人们有意burn的而不是森林大火导致。

为什么我觉得ABE都是错的……