知识点：因为17颗星星被环绕是一个客观事实，这个动作的时间不受discover的发生时间的影响，应用一般现在时

错选成D，D应为时态，there be句型后的名词才是句子的核心词，having lighting在本选项中可以做定语从句homes had electricity的伴随状语。在逻辑上，我们不能说“房子拥有光亮（home have lighting）“，只能说”房子里有光“。这是因为房子不能主动的拥有光亮。

as indicates’; we must either say ‘as indicated by ’ or simply say ‘as it indicates’ – Per se, this is a fragment
A平行错，B核心词有误，C主谓不一致，D时态+主谓不一致
标点不是最主要的考点，不要一上来就看标点

D如果用被动语态是不是也不对？indicate还是修饰A ruined structure，然后再用B的解释排除？

Ron * "namely" must be used either before a noun or before a noun phrase / clause. you can't use it directly before an independent clause. because of this principle, you can't say "namely they vary...". however, "namely that they vary..." and "namely considerable variation" are both fine. this kills (a) and (e). * "the fact of X doing Y" is universally incorrect. this kills (a).

数列里的每个数与平均数的差的和为0

知识点：
1.动名词——充当主干，即，主语、宾语、表语，的；现在分词——充当修饰，即，定语和状语。（另外，介词身后肯定是动名词短语）
2.动名词在句中是没有“逻辑主语”的，而分词会有自己的逻辑主语
3.要想给动名词或者名词添加逻辑主语，唯一的方法就是用所有格的方式，如Jack’s killing of bears

Whereas是平行制造者；
B选项错误，1是whereas连接的两个句子在逻辑上不对等，前半句“血管在哺乳动物中是平行排列的”，后半句“鸟类有血管”。后半句应该为“血管在鸟类中是平行排列的”。2是介词短语for。。。，介词短语的主要作用是在句子中作状语，因为for后跟的动名词短语，动名词的特性是在句中没有逻辑主语，所以tiny tubes必须是发出convey这个动作的施动者；
CD选项unlike比较对象不对等
E选项which引导的非限定从句，就近修饰bone cells，应是the tiny tubes平行排列

介宾短语的主要作用是在句子中作状语
介词+宾语（ie.名词、代词或名词短语）=介宾短语

ACD选项是主谓一致问题，注意句子的核心词；
CD选项中注意区别ing和不定式的区别————知识点：若发生不定式和ing转换的是状语或者定语，则判断标准细化为：变化成分的主句的发生是否对变化成分的发生与否有直接影响。若有，则选不定式，若没有，则选ing————显然，compliance of laws对require....没有影响，则选ing。

In the case "bother", you can say both "bother doing" and "bother to do" and the meanings are the same. 行吧，我还以为bother to do和doing意思有区别，查了一下并没有

ING forms aren't verbs, and so don't have a tense of their own. they just adopt the tense of the surrounding clause.

in this case, provided this problem is from a reputable official source, you can take this as proof that "to bother VERBing" is a legitimate idiomatic structure.

in fact, this may be another case in which there are two legitimate structures, but the test goes for the one that gets rid of undesirable repetition.
note that your suggested alternative contains "to" twice in the space of three words: "to bother to recover". that's considered "ugly" -- see here:

关于C选项的知识点补充
"the last" is incorrect.
* "former/latter" should be used only when there are exactly two things.
* "last" should be used only when there are three or more things.
i think that "first" can actually be used in either of these two situations (in contrast to "last", which shouldn't be used unless there are 3 or more things), but i would want to see official GMAT evidence before making a conclusive judgment on that issue.

You haven't quite understood the rule about noun modifiers correctly. The principle here is that noun modifiers should be placed as close as possible to the noun they modify. This rule applies to 'which', 'that', and other noun modifiers too. The rule isn't actually ever broken - we still try to place the modifier as close as possible - but things become more complicated when (as in the problem you cite) there are multiple modifiers. Here we have three modifiers of 'reactions', they are: 'emotional', 'in an individual', and 'that create...'. We can't have them all touching the word 'reactions'!

https://www.manhattanprep.com/gmat/forums/the-use-of-that-t33805.html

(a)
"so that" is wordy, but also doesn't make literal sense here -- "X so that Y" implies that X is an action taken toward the goal Y. i.e., i studied hard so that i could get a good grade.
needing time is not an action taken toward a goal, so this doesn't make sense.

(b)
read literally, this sentence doesn't give any indication that the workers themselves need the time -- it just states that the time is "needed" (we don't know by whom) when the workers are working.

(c)
present tense doesn't make sense

(d)
correct

(e)
present tense doesn't make sense

hypotenuse 直角三角形的斜边

B为什么不对？之前销价都因为税涨价了那这次税涨价了销价肯定也涨

文章第一句话

做第二次还是错唉！

underinvest 投资不足