1/3....1 2^n是4的倍数

比較--注意差異
T:滅絕
A1人類-A2主要非人類(反例)+自然-A3非人類(反例)

当“非数字物体（即，这个名词本身没有纯粹的数字概念，例如dogs、cats等绝大多数名词）”比较时，我们通常会用double(twice) as much as或double(twice) as many as，例如：
twice as many dogs
double as much water
但是，当“数字”比较时，我们不能加as many或as much，例如：
twice the increase
double the decrease

gmat.la/questio…p2008E1-SC-181

unqualified adj. 不合格的, 无资格的 // 无限制的, 无条件的;绝对的, 十足的
unqualifying adj.没有达到要求的
A's B prefer A是一个人 e.g. Lizzy's book
by sb 形容的是动词 “support of labor" is correct, "support by labor" isn't correct

directly是副词，只能修饰动词have或者介词短语with an ichana (dream) experience等非名词成分，但在逻辑上，其应修饰名词contact，即，直接的接触。due to通常用来表示原因而不是方法。

Either... or....连接的平行是两个名词的平行，这两个名词身后的定语在形式上是否平行没有任何关系，either...as well as...及either...along with搭配都不对

not only, but (also)，also是个副词可加可不加，表达不但…而且的递进关系

Not only... but also 须知道几个知识点：1）not only 位于句首时，须倒装；2）not only ...but also ...表示连接的两者是递进关系，即两者是同方向的，要好都好，要不好都不好 3）成分平行原则，如not only +SVO, but also +SVO or S+not only + VO, but also +VO
but 是连词，须连接两个同是拥有主谓的句子

关于排除E，需要记住一个知识点：像strategy, plan这样的主语，大部分情况下也应该理解为主观性是比较强的
比如说，"The best strategy of country A is to make its citizens rich." "My plan is to review GMAT 3 hours a day."只要主语是plan类的，对表语所描述的事件都有“主观”的影响（表语讲的事件肯定是计划的内容，自然是被主观控制的嘛）

used to pay; went to pay both Ok. used for paying , wrong
Ron: Used for __ing" is more indirect. E.g., My father uses this chair for watching television, but my father uses his eyes to watch television.

There is no significant difference among manufacturers 討論製造商之間價差,非price gap between store&brand

A such projects are not adequately reflected in the country's GDP

AC比較
over the eighteenth century副詞位置改變,修飾整句變成修飾 tripled而已
A 平行 詞性作用平行
C With相較because因果表達不清

clear picture of the patterns and causes of ocean currents "has emerged"
B 平行錯誤 their通常不指代所有格

除了关系副词（where/why/when),关系代词(which/who/whose/that/whom)在先行词作定语从句中作宾语的时候可省略。 ps. 到底什么是约束力?

whose既可以修饰人、也可以是物品，只要有所有格就行

E还有一个错的点
as long as you mention some specific "X" earlier in the sentence, then "such an X" is fine, yes.

another example:
i have no problem with using a standard geometry textbook; indeed, such a book is helpful in providing ready-made sets of practice problems.
--> "such a book" is legitimate because the sentence has mentioned a particular book (namely, a standard geometry textbook).
such + noun 中的noun一定要在前文中出现过

like 对比只能更名词/名词属性
As (would ) be the case with

吸烟”和“抑郁”这两个事件在前提中具有统计关联，即，the incidence of depression among those who had taken up smoking was four times as high as it was among those who had not。

推理结构为：

前提：凡是“吸烟”的人都更容易“抑郁”（“吸烟”和“抑郁”之间存在正相关关系）
结论：吸烟导致抑郁

选项分析：

A选项：Correct. 相对于那些在不抑郁的人，凡是那些在研究最开始就抑郁的参与者不会更有可能成为吸烟者。本选项既谈到了“吸烟”，又谈到了“抑郁”，因此可以保留。实际上，这个选项内含的意思是：抑郁不会导致吸烟。若抑郁会导致吸烟，那么显然可以削弱推理文段，属于CQ3：因果方向问题。现在将该削弱项取非，自然可以加强推理文段。

80*(1-90%) =8 →There are 8 people ahead of Amy in her class
Combined with another class, there are 19+8=27 people’s grades ahead of Amy’s.
# of people whose grades below Amy’s / total people of twp class → (100+80-27)/(100+80)=85%