Qualify一个观点的含义是让这个观点更加详尽，以便可以抵御这类challenge

by Ving 暗示主语是主句主语，in Ving 没有主语！！！！

介宾短语的动名词没有主语问题！！！！！！！again

E中which定语从句，依照就近修饰原则的话，不是错了吗

体会bc语义差异；c限制性定从，从句focus on “have”这个动作、b非限制性定从，从句focus on “require”

compare to 的主语应该是主句主语，此处为there 错

同位语修饰整个句子是必须是抽象名词，是具象名词时只能修饰前一个名词

tortoise单数，

注意为划线部分a variety

作了18年主席而不是前主席，前主席不用加时间段，因为不可能停止成为前主席

是a不是d
读懂搞定一切

选对了但是耗时过长！
注意到代词指代问题！

注意理解句子重心的变化
because的是humidity的变化（由游客带进去的moisture）

the real problems with choice a:
- 'the ratio of 42 times' is redundant; it'd be good enough just to say '42 times'. note that the word 'ratio' is not redundant in choices c-d, since it's being used as a modifier to make a logical connection.
- it doesn't say 42 times what. not only is that unacceptably vague, but it also breaks parallelism.

i think the combination of "amount" and "as much as" would be tagged as redundant and therefore wrong.

i am not 100% on this, as the gmat's usage preferences are rather slippery at times, but there's no doubt that this suggestion is inferior to the version without "as much as".

shorter versions:
amount X is twice as much as amount Y --> inferior, and possibly even wrong (redundant)
amount X is twice amount Y --> undoubtedly better

D 方案相关的题 只要能达成目的就行 不需要是最好的方案
只要SPK004比目前种的 有更多beta-carotene就可以， 不需要SPK004含有最多的beta-carotene

just look at the parallel structures side-by-side, and notice which parts match up to which other parts.

/the total amount of pollutant/ emitted annually by vehicles at the O'hare International airport
is twice
/that /emitted annually by all...

我的解释：
①原句中强调了all，如果省去的话会改变原句的意思，所以排除BE
②A中as much as that which ...(that which 很wordy）排除A
③as much + compared to 错误
选C

逻辑gap 只要不漏油→没污染， gap是除了漏油没有其他污染

Ron： i'm loath to use apostrophe + "s" for anything but humans, animals, and the like.
‘s在表达上相对有限制==》拥有某种东西
of sth 也表示拥有，但可以说一些非物化的，比如拥有特征之类的