? 实体名词和动词性名词不能平行（逻辑平行范畴）
实体名词即那些表示实际物体的名词，如：
rock，chicken，egg，light，desk，table…
动词性名词，包括词义为表示动作变化的名词、由动词衍生出的同根名词以及-ing形式的动名词，如：change, development, pollution, eruption, growth, swimming, running, skiing…..
? 简单的动名词和其他动作性名词也不能平行
1） 什么是简单的动名词：其实就是现在分词！是在句子或短语
中仍然是动词的作用和性质，但由于搭配介词、表示伴随、表示修饰，作主语或充当谓语外的其他成分等原因把动词形式改成了-ing形式。
Example:
Wrong: The rebels demanded the withdrawal of government forces from
disputed regions, significant reductions in overall troop levels, raising the rebel flag on holidays, AND a general pardon.
分析：这里raising明显不对，在短语“raising the rebel flag on holidays”里还是做动词用！只是因为有介词form，所以要变成-ing形式，这就是现在分词！！！！！
2） 要想和其他动词性名词平行，就得把动名词复杂化，把它变成真
正的名词作用。一般的，就是在动名词前面加量词a, an, the或者在动名词前面加形容词，然后再在动名词后面+of…，这样彻底就变成名词了。这样的动名词短语才能和其他动词性名词平行。
根据这个规律，上面的错句子应该改成：
Right: The rebels demanded the withdrawal of government forces from
disputed regions, significant reductions in overall troop levels, THE raising OF the rebel flag on holidays, AND a general pardon.
? 如果这个动作本身就有名词形式，就不要去创造一个动名词短语形式。
Example:
Wrong: The rebels demanded the withdrawal of government forces from
disputed regions AND releasing certain political prisoners. Wrong: The rebels demanded the withdrawal of government forces from
disputed regions AND THE releasing OF certain political prisoners.
Right: The rebels demanded the withdrawal of government forces from
disputed regions AND THE RELEASE OF certain political prisoners.
? 动名词要避免用“X’s+动名词”形式, 可以用“物主代词+动名词”（有效性错误） ? 谓语动词只能和谓语动词平行
The plant BOTH exceeded output targets AND ran more smoothly than ever.
? 不定式和不定式平行
1） 除了第一个不定式，其他不定式都可以省略to，但格式要一致，
省略to就都省略，不省略to就都不省略：
Example:
Wrong: It is critical to suspend activities, to notify investors AND say
nothing.（红色字体部分格式不一致）
Right: It is critical to suspend activities, notify investors AND say nothing.
2） 当第一个不定式前面有parallel maker时，后面的不定式的to都不
可以省略：
Right: It is critical either to suspend activities or to notify investors.
分析：“either”就是parallel maker
这样的parallel maker有：
both…and…; not…but…; not only…but also…; from…to…; either…or…; neither…nor…; distinguish X from Y, As X, So Y, estimate X to be Y, compared to X, Y…, think of X as Y, consider X Y, make X Y, declare X Y, Mistake X For Y, Whether X Or Y, regard X As Y
? 形容词、现在分词、过去分词可以平行（分词作定语时）
Example:
A mastodon carcass, thawed only once AND still fresh, is on display. Only a few feet wide BUT spanning a continent, the railroad changed history. ? 不定式和现在分词在句尾的区别
1） 不定式在句尾表示目的
2） 现在分词在句尾表示结果或伴随
Present Participle: Investors sold the stock rapidly, CAUSING panic. Infinitive: Investors sold the stock rapidly TO CAUSE panic.
如果句中没有明确表示是指目的，就用现在分词！
? 从句平行
从句只有和引导词相同的从句才可以平行！除此之外，和任何词、短语、从句都不平行。
Example:
Wrong: A mastodon carcass, thawed only once AND which is still fresh. is on display.
Right: A mastodon carcass, which has been thawed only once AND which is still fresh, is on display.
? 关于either…or…的平行
Either…or…在句子中位置的不同，导致平行的变化如下（OG SC 56）： A．
either在动词前面:
??either fashioned from the spotted sandstone of Mathura or fashioned
from Gandharan grey schis.
B． Either 在介词前面：
??fashioned either from the spotted sandstone of Mathura or from
Gandharan grey schis.
C． Either 在名词前面：
??fashioned from either the spotted sandstone of Mathura or Gandharan grey schis.
? 总结：平行的8大常见考点
11、 比较结构
? 比较结构的信号词：
? 最重要的四个信号词是：like，unlike，than，as！遇到这四个词，
就一定要注意比较结构的考点。先找出比较的两个对象，然后从逻辑上判断这两个对象是否是同种性质相比较的；从语法上判断是否语法结构平行。
下图是其他比较结构信号词：
? as 和 like（更高阶的请看曼哈顿P248-249）
? like
1) like是一个介词，后面只能跟名词、代词和名词短语，不能跟
从句和介词短语。Like是用于两个名词间的比较的。
Right: LIKE her brother. Ava aced the test.
2) Like后可以跟动名词：like swimming，running….
3) Like不能用来举例：\
phrase such as, rather than with the word like, which suggests a
comparision.\
Such as在举例的时候，可以分开，如：such crops as corn and beans
4) unlike和like短语都可以放在句首或句尾。此时，跟在unlike和
like后面的名词都只是与句子主语作比较
? As
As是可以当介词（引导名词），也可以当连词使用（引导句子），as当介词时，不是比较的作用，也不是“相似”的意思，而是翻译为“作为”的意思，所以只有当as是连词时，才能表比较。因此as只可以引导两个完整句子的比较，不能引导两个名词的比较。
Example：
Wrong: LIKE her brother DID, Ava aced the test.
Right: AS her brother DID, Ava aced the test.
在GMAT中，as和like都可以引导比较，不过as引导句子，like引导名词，如下例：
Right：Like her brother, Ava aced the test Right：As her brother did, Ava aced the test.
As作比较时的变体固定搭配
Right: JUST AS the trains were late yesterday, the buses are late today. Right: JUST AS the trains were late yesterday, SO TOO are they late today.
? 逻辑上平行
即两个用于比较的对象要是相类似的东西，是同性质的东西。
Wrong：Frank's build, LIKE his brother, is broad and muscular.
以上这个句子中，比较对象是“Frank’s build”和”his brother”，体格和人怎么能比较呢，所以是逻辑上不平行，逻辑错误。正确的表达方式有以下两种，其中第一句中的相同的词“build”就省略了，避免重复；第二句用that代替build也是可行的方法。
Right: Frank's build, LIKE his brother's, is broad and muscular. Right: Frank's build, LIKE that of his brother is broad and muscular. Right: Frank, LIKE his brother, has a broad and muscular build.
? 语法结构上平行
详细内容参见平行那一章
? 词语省略（只要逻辑合理，重复的都能省，所以逻辑为王！）
? 在比较结构中，所有格’s后面的重复内容通常都省略
My car is bigger than Brian's [car}. My toes are longer than Brian's [toes}. My car is bigger than the Smiths' [car}. My toes are longer than the Smiths' [toes}.
? 只要没有歧义，重复提到的单词、词组甚至是句子都可以省略
In general, you should put in the omitted words or appropriate Helping Verbs (such as be,do, and have) only if you need' to remove ambiguity.
Example：
Right: Whereas I drink 2 quarts of milk a day, my friend drinks 3 [quarts}. Right: I walk faster than Brian [walks}.
Right： I walk as fast now as [I walked} when I was younger.
? 怎么判断产生歧义与否
一般的，比较对象在句中都充当同样的成分，如主语或宾语。如果在后的比较对象既可以理解为在原句中充当主语，又可以充当宾语，