掌握基本套路，先写出一个正确的句子
研究生毕业的综合考试之前，语法课的老师用一节的时间给我们讲了一下有关句子的语法。 一来是教我们语法知识（我们是TESOL专业）， 二来是希望我们在考试中写的答案别太丢人。内容其实很简单, 不过展现的方式很独特，和我们传统的语法术语相比，这种方式更形象更容易理解。在此分享给大家，希望可以帮助大家写出一个正确的句子。
注意文中提到的四个主要概念: trunk, shifter, linker and insert
Trunk
Trunk是大树的主干，也就是我们熟悉的主谓宾（SVO）结构。一个Trunk就是一个完整的简单句，例如I love you. 当两个Trunk连在一起的时候，常见的有三种情况：
TRUNK PLUS TRUNK (T,+T)
两个主干在一起: 简单句+简单句构成“复合句”（compound sentence), 中间用逗号隔开, 并用连词连接。英文中有7个主要的连接词（其它的像however都是副词）, 便于记忆我们称之为BOYFANS (but, or, yet, for, and, nor, so)
These leaves provide shade, but the tree also gives wonderful fruit.
love her, but she loves him.
(T;T) (using sparingly)
两个句子也可以在没有连接词的情况下也可以, 不过要用分号来隔开。
Poverty is a major problem today; it must be dealt with first.
I love her; she loves him.
TRUNK WITH TWO VERBS(T=)
一条主干可以“分叉”，同一个主语有两个动词的话不需要用逗号。
The fruit has nutritional benefits and tastes good.
Everyone creates his own heaven or create his own hell.
Shifter
Shifters can shift. In other words, they can move. They’re the part of a sentence that connects to a trunk, to add some important information. The trunk is solid, with its SVO, but the shifter can move, like leaves in the wind. The meaning doesn’t change.
为了给主干补充信息，我们可以利用shifters。Shifter通常是一个不完整的句子，它需要依附在完整的主干上。基本的结构是：SHIFTER, TRUNK (S, T) ，也就是我们常说的“复杂句” （complex sentence）。Shifter (下面红色部分)和trunk连接，如果shifter中含有动词的话一般就要加逗号。
If people don’t stop wasting natural resources, there will be shortages. (红色部分为shifter，因为位置是在前，我们称之为front shifter, 其后要用逗号与trunk隔开)
There will be shortages if people don’t stop wasting natural resources. (当我们把shifter放在后面，他就成了end shifter, 此时逗号就不需要了)
Since the invention of guns, wars have increased.
Whenever there is unemployment, crime is likely to increase.
In English the order of words is important.
Yesterday the weather was rotten.
注意最后两个句子中In English, Yesterday之后并没有加逗号。老师说 “When in doubt, leave it out” -- 当不知道该不该加逗号的时候就不要加，否则的话容易使得句子读起来不连贯。 很多时候标点使用取决于写作者的自行判断。
Shifter一定是要依附trunk的，不可以单独存在。如果我们直接写: If people don’t stop wasting natural resources. 这会是一个错误的句子, 被称为fragment，读一下下面这些例句，很可能你也写过这样的残句：
Linker
A linker is a word or phrase that connects the ideas between one sentence and the next. (Link means connect.) Linkers usually go at the beginning of a sentence, so they start with a captial letter.
它的基本结构式LINKER, TRUNK (L,T)。注意一定要有逗号，尤其是用到however, therefore的时候。
Obviously, we are talking about bananas here.
As a result, he writes English well.
Insert
If you want to make your writing sound more sophisticated, start with a trunk (SVO). Then add more information to the subject, the verb, or the object. We call this extra information an insert, because you insert it into the sentence.
TRUN INSERT (TI), Insert为红色部分，注意标点
The treepicture above, a banana tree near a hotel parking lot, is growing in Haiti.
Television, which influences everyone, has advantages and disadvantages.
EmmaWatson, a British actress, is my goddess.
以上这些内容是英语中的基本结构：simple sentence, compound sentence以及complex sentence。我们先从写好一个句子做起，然后可以写出更复杂一些的complex-compound sentence，例如：
Catch-22 is widely regarded as Joseph Heller's best novel, and because Heller served in World War II, which the novel satirizes, the zany but savage wit of the novel packs an extra punch.
在这个基础之上再进一步的话，就是要学习句子的多样性。主要涉及的是非谓语动词、独立主格的使用。例如下面这两个句子可以通过非谓语动词合为一个句子：
(1) Captain Lewis allowed his men to make important decisions in a democratic manner.
(2) This democratic attitude fostered a spirit of togetherness and commitment on the part of Lewis's fellow explorers.
(1+2) Allowing his men to make important decisions in a democratic manner, Lewis fostered a spirit of togetherness and commitment among his fellow explorers.
下面这两个句子可以通过独立主格写成一个句子：
(1) Lewis's fame and fortune was virtually guaranteed by his exploits.
(2) Lewis disappointed the entire world by inexplicably failing to publish his journals.
(1+2) His fame and fortune virtually guaranteed by his exploits, Lewis disappointed the entire world by inexplicably failing to publish his journals.
我们平时在阅读的时候也要注意看清句子的套路。只有看清了套路我们才能理解得更透彻和学以致用。不要再纠结名词性定语从句形容词性定语从句了，它们只是句子套路中的一个成分，绝不是因为用了从句这个句子就“高大上”了。先写好一个句子，然后通过赏析、模仿、造句，写出一个漂亮的地道的句子。
纽约时报》专栏作家、大学教授Stanley Fish就是一个“句子迷”，他称自己为“a sentence watcher”。有兴趣的话可以读一读他的How to Write a Sentence，回复关键字"522book"可以获得这本书的电子版。