修饰(对修饰语的种类要敏感，verb modifier的位置)
1，due to/ because of/ because
Due to=caused by，只能修饰名词。不能做状语修饰整个句子!
Because of只能接名词，修饰的是整个句子，做原因状语。
Because接句子，修饰主句，做原因状语。
和due to一样，similar to, different from也只能修饰名词，不能放在句首
2，
(1)Prepositional Phrases(介词短语)既可以做Noun modifier，又可以做Verb Modifier。所以只有通过the context of the sentence来判断!Noun modifer的位置变动会造成歧义修饰，Verb modifier的变动会造成夹心修饰，所以一定要注意介词的位置!
(2)comma+preposition modifier和comma+infinitive是adverbial modifier。修饰整个句子的意思。判断是否为adverbial modifier，就是能否回答how/why/when/where之类的questions。
(3)now的出现，一般是强调the present和the past的区别。Now是副词，注意位置和修饰对象
3，
形容词开头的修饰：1>修饰主句主语;2>和主句内容有一定的联系。
if it's an adjective, you DO use a comma. 如果前面不是职位、称号，而是一个形容词，那就要用逗号。
Creative and original, Thelonious Monk ... --> correct
同位语：同位语由unrestricted adjectival phrase而来，同位语的修饰对象：名词或名词短语或代词
1)、同位结构的特征
(1) 起修饰语的作用,一般用于修饰名词或名词短语;“解释的是整个名词，不是名短中某个词”，故同位语不是核心词修饰。
(2) 必须对其修饰对象具有解释力;
(3) 位置：名词前或名词后，一般在修饰对象的后面;
(4) 不影响主谓一致(谓语应该和主语保持一致，而不是和同位语);
2)、同位结构的形式
(1)名词性同位语：名词解释名词。(以下三种，第二个n.后可以跟修饰词)
i) N., n.;
ii) n., a/an + n.或a/an + n., n.;
iii) the + n., n.(前面的the + n 为同位结构)
(2)同位语从句：抽象名词(theory/evidence/belief/principle)+that 从句，that 从句对抽象名词进行具体化解释(注意与of 结构的区别)，that从句部分才是同位语。That不可省略。不充当成分
(3)概括性同位语：用一个概括性的名词去概括前面的修饰对象：短语/句子，n. +that/doing/done...如果修饰句子，句首出现了连词，如because，就不能使用这种结构
(4)名词重复性同位结构：n,n(重复所修饰的名词)+that 定语从句
(5)代词代替性同位结构：n,one/ones+that 定语从句
关于同位语用法中的the和逗号(如B选项中的TM, the jazz pianist and composer)--摘自Manhattan：
1. if you preface someone's name with a noun describing their occupation (or other word describing what that person does), WITHOUT AN ARTICLE, OR WITH THE DEFINITE ARTICLE "THE", you DO NOT use a comma. 如果把职位、称号放在人名前面，如果没有冠词，或者有定冠词，就不用逗号(本题的情况)。
example:
Jazz pianist and composer Thelonious Monk ... --> correct
注意：
(1) if you are using "THE (description) (name)" to introduce someone for the first time, then you DON'T use a comma.但有要注意：当职位、称号前是定冠词时，如果是第一次提到某人，是不必用逗号的
example:
The author Ernest Hemingway was known for his drunken and violent escapades.
--> here we are introducing hemingway, so we don't use a comma.
(2) if you have already introduced two or more people, but you are using "THE (description) to single out one of them, then you DO use a comma.
example：
Among her friends were an author and a painter; the author, Ernest Hemingway, went on to become an icon of American literature.
--> we've already introduced "the author"; this time we use a comma to single him out.
2. if there's an indefinite article (a/an), you DO use a comma. 如果前面有不定冠词，就要用逗号。
example
A jazz pianist and composer, Thelonious Monk ... --> correct
4，Comma+Ving的总结
1>分词短语在句首作状语:逻辑主语=主句主语
2>在句尾时，Comma+Ving的修饰，它必须和前句的内容有关系!若为无关则不使用ing：
Wrong：Lisa speaks in front of many people, standing 2 feet tall。演讲能力和身高并没有联系!
若有关系：
(1)表伴随：1>修饰句子的主语;2>同时进行的动作
(2)表结果：整个句子是原因，分词动作表示前面整个句子的最直接结果。(immediate, essentially unavoidable results。例如：The bullet entered Smith’s head, killing him instantly)
(3)如果前面是主系表结构(逗号隔开)，V-ing结构依然修饰的是整个主系表结构，所以后面的V-ing结构也可以被解读为修饰前面的名词成分—主语，对前句进行补充说明。
例如：animal-hide shields were essential items of military equipment, protecting warriors against enemy arrows and spears.
(4)Comma+ving的例外情况：including, including是介词而不是ing修饰语。Including中的短句中不能出现also, as well等词!
(5)关于分词修饰语的理解：Prep08—第二部分181
(6)GMAT的陷阱，注意区分：
1，birds overcome by pollution fell from the sky, prompting officials to.....注意，是这件事促使官员......。
2，birds overcome and felling from the sky were promting the officials to.....这句话的意思就变成了这种鸟促使官员.....
定语从句与分词短语作定语的区别：
1) 定语从句强调具体时间具体动作,以及动作的一次性;
分词短语强调笼统不确定的时间，抽象/客观/重复性/多次性的行为
2) 都可以接受时,分词短语优于定语从句(更简洁),定语从句要转换为分词短语(但不能引起歧义或破坏平行)
3) 定语从句包含情态动词时不能转化为分词短语
介词或介词短语+ing分词: in addition to/in/by/without/besides+doing…,句子
Ø 在句首,逻辑主语=句子主语
Ø 在句尾,逻辑主语可能是句子主语也可能不是
嵌入式关系分句，详解如下：
“有一种关系分句(即定语从句)，它既是先行项的后置修饰语(即定语)，同时又是另外一个分句结构的宾语(即宾语从句)”此分句结构就被嵌入在定语从句中，即嵌入式关系分句。
该书举例：In his breast-pocket he had a patch of scarlet, which i suppose was the paper cap serving as a handkerchief.
注意两点：
1)从句which was the paper cap serving as a handkerchief 首先是 patch of scarlet的定语从句。
2)从句which(patch of scarlet) was the paper cap serving as a handkerchief 也是i suppose 的宾语从句，即I suppose (that)the patch of scarlet was the paper cap serving as a handkerchief 。
综上所述，当一个定语从句同时是另一个主谓结构的宾语从句是，就可以写为嵌入式关系分句。
5，法律，条例等的修饰，despite的用法
Despite做介词，和in spite of同义，都表示“尽管，虽然“。接名词或名词性短语。接动名词时，逻辑主语为主句主语。
Despite wanting to see him again, she refused to reply to his letters.
描述文件，法律，条例等的内容，使用doing，目的使用to do。法令的内容通常以分词引导表效力的延续性，如laws, agreement(prep 1-221)和directive，后面不跟定语从句。
6，
(1)some time/ sometime/ some times/ sometimes
分开是一段，相连为某时;分开s为倍、词，相连s是“有时”。
(2)especially是表示程度，specially表示特殊
7，when的用法。时间状语位置的改变会引起句意的改变
(1)when作为关系代词引导定语从句，修饰句子中的时间名词或时间，可用in which替换(in which中的in提前问题，因为以一个介词结尾的句子是不正确的!)
(2)如果不能用In which替换，那么就是做时间状语，意思为at the same time“同时发生，当....的时候”。表示主句事件在该时间发生。
(3)If’ and ‘when’ can be used interchangeably when we present conditions in which the outcome is definite or the outcome is a general fact.
i.e. if event A happens, event B happens.
Example 1 – We know as a general fact that water evaporates when it is heated.
If you heat water, it evaporates. – CORRECT`
When you heat water, it evaporates. – CORRECT
When ‘if’ conditional statement is used to express a situation in which the outcome is a possibility and not a certainty, ‘when’ cannot be used in place of ‘if’.
Example 2 – Tom is not certain if by exercising he will lose weight or not.
Considering his not so high success rate in losing weight, Tom knows that if he exercises, he may lose weight. – CORRECT
Considering his not so high success rate in losing weight, Tom knows that when he exercises, he may lose weight. – INCORRECT
(4)Before/after是不能和when一起使用的
8，其他从句引导词
<1>What不能引导定语从句
what引导的名词性从句中从句谓语动词的单复数情况：
what后面“什么时候用单数,什么时候用复数”根据动词后面的名词的单复数来定.
(1)What在从句中做主语，主句谓语由what从句的谓语决定。
What is difficult to understand is A.;What are difficult to understand are A and B.
(2)what在从句中做宾语，主句谓语由主句表语/宾语决定what they want are XX,XX&XX。
What his father left him are a few English books.
<2>Where可引导定语从句，可引导地点状语从句
<3>如果名词是复合名词，A and B，那么who的定语从句要修饰整个复合名词(both A and B)
<4>Which的指代小结：
(1)通过which的单复数来判断到底修饰哪一个
(2)通过时态来判断
<5>that和其他关系代词补出的问题
(1)定语从句以及其他任何从句，如果并列而且从句主语不一致时，就要补出先行词。例如：the boy who I feared, and who many people loved was her boy friend
(2)两个相同的从句并列(如两个定从，两个宾从)，主语一致时，可以从句内部并列。例如：The big bang theory that the universe began in an explosion and has been expanding ever since.
9，opening modifier和主句之间不能插入成分，必须马上接被修饰语。 it automatically refers to whatever immediately follows the comma
状语从句的省略：
1) 两点省略要求：
第一点是毫无疑问的：逻辑主语等于句子主语
第二点也是必须的：从句的谓语必需是be(没要求主句谓语也必需是be!换句话说状从的省略可以看成是省略了一个be)，且从句主语和谓语要么同省，要么同留。
2)形式
正确形式: 表示时间/条件/让步的连词(when/while/if/unless/although/even if) + 形容词短语/-ing短语/-ed短语
错误形式:表示时间/条件/让步的连词 + 介词短语/名词短语 (although just inside the orbit of Jupiter是错的。逻辑主语等于句子主语，所以when a child/ when children是错的; if + n.也是错的)
特殊情况:once可以加介词短语/名词短语; whatever可以加名词短语
10， 关于夹心修饰 (by aeoluseros)：
所谓歧义修饰，是因为引发了不同的理解，而并不是语法上是否会有不同的修饰，所谓夹心修饰也是这个原则。很多人对“夹心修饰”都有过一个误解，认为S, v-ing, V. + O.结构中，v-ing既可以往前修饰S，也可以往后修饰V就是夹心，而实际上夹心并不是“可以往前修饰S，也可以往后修饰V” 。在S, v-ing, V. + O.这样的表达中，v-ing约定俗成只伴随修饰动词，见下例：
prep 2-104 The yield per acre of coffee berries varies enormously, because a single tree, depending on its size and on climate and altitude, is able to produce enough berries to make between one and twelve pounds of dried beans a year.
这个句子里depending不能改为dependent，因为depending和dependent的区别在于，前者伴随修饰谓语动词is able to produce，后者则是修饰名词single tree，会造成逻辑上不对。用dependent时："依靠于size的一棵树能够长出足够的浆果"。用depending时，“一棵树取决它的size来做到长出足够的浆果”。