in the case of an initial subject-less modifier in front of a comma, the modifier should always be followed IMMEDIATELY by the noun / noun phrase that's being modified.

问J>M?
1. M>500 单独不行
2. J = 2M-400 单独也不行
1+2： J=2M-400, J-M=M-400; 又M>500, M-400>0, 所以J-M>0, J>m

K9=K7+K8=K5+K6+K6+K7=k5+K6+K6+K5+K6=2K5+3K6, K5已知，给K6能求K9, （2）正确；
又K6=K4+K5, K5已知，给K4能求K6，也就能求K9， （1）也正确

in general, "so [adj/adverb] that [complete sentence]" is used when "[complete sentence]" has a DIFFERENT SUBJECT than the original sentence.
e.g., When I came back from vacation, I was so tan that my friends didn't even recognize me.
(subject changes from "i" to "my friends")

if the subject is still the same, then "so [adj] as to [verb]" is a more efficient way to write the construction.

The question you should really ask yourself is, "Are we talking about something that X can do?"
If the answer to this question is yes -- regardless of whether X is a person or an animal -- then "(un)able" / "(in)ability" should be fine.
If you're talking about something that someone can do to or with X, then you shouldn't use those words.

as for (d), i'm not sure whether you're allowed to insert "not" between "enough" and "to".

i also find something a bit awkward about the use of "unable" to describe something that's not actually an inability of the subject.
this plant is unable to perform photosynthesis.
legitimate, because this actually describes an inability of the plant itself.
this sentence:
they (= major economic shifts) are unable to be distinguished...
！ we're not actually talking about an "inability" possessed by the economic shifts themselves.

这分我不要了行不行。

看了答案感觉都会。

细节题

C 只是说了commentaries没有appear出来 和E对比appear很重要

选项C具有一定的迷惑性。

P：疫苗被病毒感染了
C：这些被感染的疫苗导致了m癌症

A. 无关
B. 现在的技术可以使疫苗不被感染，不能说明癌症是由于之前感染的疫苗导致的
C. 最近发现的1960年代的疫苗里面还有猴子病毒。重复了前提，重复前提不能加强结论
D. 一小部分m癌症病例中没有接触过a。与前提无关
E. 在芬兰疫苗都没被污染，m癌症的样本中不含猴子病毒。因为非A，所以非B。加强结论

程序使语言能被理解>语言能被程序理解

A比较对象有误，应为ever had done

D为什么不对啊？打折卖出商品，然后去还贷呀。。。。难道说打折卖还亏了不能还贷。。。那也想太多了吧。。。。。。

each year 和annually重复冗余！！！！！！

simply的修饰问题，需要but后补充系动词，否则simply修饰无意义

nine times more than

注意同位语，production应该是brain growth和increase in neurons