Grammar and Punctuation
這篇文章是 Coursera 上 Academic English: Writing 專項課程的第一門課程的課程筆記。主要是一些語法和標點符號的使用，很基礎，但是又很容易弄錯。
共有三種類型的句子。
- 簡單句
由主語和動詞構成，又稱作獨立分句。
Sam washed his face.
- 複合句
由兩個簡單句或兩個獨立分句組成，將兩個獨立分句連接即可。
Sam washed his face, and he combed his hair.
- 複雜句
含有一個獨立分句，和一個或多個從屬分句。
Sam got dressed because it was time for school.
並列連詞
並列連詞有：
and / but / or / nor / yet / so / for
以下爲使用並列連詞的簡單句示例。
- The computer is old and broken.
- Sam washed his face but not his hair.
- We will go to the park or the market.
- She bought apples, pears, and grapes.
注意到上面的第一句和最後一句都是使用 and 進行連接。但是第一句只有兩個名詞，所以不能用逗號連接；有三個及以上的名詞時，一定要在名詞相互之間用逗號連接。
複合句 (Compound Sentence)
第一種複合句
我們可以使用連詞將兩個主句連接起來構成複合句。常用的連詞有：
and / but / or / nor / yet / so
形式如：
- The waiter brought us some water**, and** we looked at the menus.
- The cyclist used all of his energy**, but** he rode up the steep hill very slowly.
第二種複合句
我們可以使用轉折詞構成複合句。常用的轉折詞有：
therefore / however / in addition / thus / furthermore
similarly / otherwise / then / nonetheless / also
consequently / finally / indeed / likewise / moreover / nevertheless
這種類型的複合句還需要額外使用到分號和逗號，具體形式如下：
- I was late to work**; therefore,** my boss is not happy.
- Saving money is not easy**; however,** it is a good habit to follow.
以上是將轉折詞放於句子中間的用法，實際上，轉折詞還可以用於句子開頭（但是這種情況不屬於混合句的範疇）。如：
- Likewise, my teacher told me to start studying.
- Nonetheless, we need to start using water more wisely.
第三種複合句
當我們有兩個句子非常緊密的聯繫的時候，並且有"and"的意思的時候，我們可以用分號直接連接。
如：
Susan is very healthy**;** she usually walks to work.
The music was loud**;** everyone was dancing.
總結
所以總的來說，總共有三種複合句。如下：
- 用逗號和連詞（如 and, but, so）
- 用分號，轉折詞（如 therefore 或 however）和逗號
- 只用分號
狀語從句 (Adverb Clauses)
以句子 “While Sam washed his face, we listened to music." 爲例。從屬子句的部分是，"While Sam washed his face"，因爲有 "While" 所以這個子句是不能獨立成句的。所以從屬句是用狀語從句連接詞開始的。
每個狀語從句能用兩種不同的方法來寫。如：
While Sam washed his face, we listened to music.
We listened to music while Sam washed his face.
Jeff ate an apple when he got home from work.
When Jeff got home from work, he ate an apple.
即，如果用從屬句開始一個句子時，需要使用逗號連接；如果用獨立從句開始一個句子時，則不需要使用逗號。
以下是一些常用的狀語從句連接詞：
after / although / while / when
before / since / if / because
even if / whether or not
in case / unless
so that / even though
更多使用逗號的情況
介紹性短語 (Introdutory Phrases)
介紹性短語一般獨立放在句子開頭，然後使用逗號將其與主句進行分隔。
- Due to the bad weather, our game was canceled.
- On Monday, my teacher announced a test.
- After dinner, Steve watched the news.
- Because of traffic, we were late to the theater.
- For several months, I have been playing the guirar.
打斷性短語 (Interrupting Phrases)
通常我們可以在主語和動詞之間看到打斷性短語，但是實際上，他們可以放在句子的任何位置。
The mayor**, by the way,** will be at the meeting.
This is the reason**, therefore,** that you should buy a house.
Joe wants to buy a house**, too.**
還有類似於定語從句的打斷性元素，如下
My roommate**, who hates seafood,** doesn't want me to cook shrimp.
The dress**, which I bought for tonight,** is too tight for me to wear.
關於轉折詞的使用
以轉折詞 therefore 爲例。當它使用在複合句中時，形式如下
Jane loves books; therefore, she reads them all the time.
當它作爲介紹性短語時，形式如下
Jane loves books. Therefore, she reads them all the time.
當它作爲打斷性短語時，形式如下
Jane loves books and, therefore, reads them all the time.
所以當轉折詞在不同的使用場景時，需要注意標點符號的使用。
平行結構
平行結構的句子，並列的部分都要使用同樣的形式。如下
- He loves to swim and sleep.
- Cake and cookies are both fattening.
- We were hot, tired, and thirsty.
以下是常用的一些連接器，需要使用平行結構。
- ____ and ____
- ____ but ____
- both ____ and ____
- not only ____ but also ____
例句如下。
- I was looking for an apartment that was both close to my work and easy to afford.
- I want to find a gym that is not only close to my apartment but also affordable.
其中下劃線部分都是形容詞短語。
以修改下句爲例。
He is afraid of being alone but not to die.
我們可以發現下劃線部分並不是相同的形式，其中 being alone 是一個動名詞，而 not to die 是一個不定式。所以我們可以改爲下面的形式。
He is afraid of being alone but not dying.
句式多樣性 (Sentence Variety)
句式多樣性指的是使用多種類型的句子。
第一種方法實現句式多樣性是使用不同類型的句子。有以下四種類型的句子
- 簡單句 （Simple)
The grass grows in spring.
- 複合句 (Compound)
Grass grows in spring, but it dies in winter.
- 複雜句 (Complex)
Because it is too cold, grass doesn't grow in winter.
- 複合複雜句 (Compund-Complex)
Because grass needs warm weather, it doesn't grow in winter, but it grows in the summer.
第二種方法實現句式多樣性是使用不同的句首。有以下幾種開始句子的方式
- 副詞 （Adverbs）
如 Quietly, Every day, Frequently
- 先行短語 (Prepositional Phrases)
如 In the morning, Due to stress, After work
- 其他轉折詞
如 The last reason ..., Another cause of...is..., For example, Furthermore
第三種方法實現句式多樣性是使用不同長度的句子。
- 短句
使其精煉。但是我們大量使用或全部使用短句，會顯得寫作風格 choppy。
- 中等句
一般 10 到 15 詞。
- 長句
一般 20 到 40 詞。
第四種方法實現句式多樣性是使用同義詞。
- 重複重要的名詞
需要注意的是，重要的名詞是需要重複的。這樣做，能讓讀者在你的思路中明白你要講的東西。
The employee.......the employee......employees........
- 使用同義詞來達到多樣性
不重要的名詞，可以使用同義詞來避免文風顯得無聊。
The employee.......workers........a worker.........the staff........employees.........
- 用不同的方式表達同一件事
The employee........the worker........the person working in an office.........a hired person..........someone employed.........
使用這四種方法，可以創建一種屬於你自己的比較好的寫作風格。
當寫文章時，可以參考以下這些步驟。
- 選取話題 (Pick a topic)
- 進行一些寫作構思 (Do some pre-writing)
- 書寫文章主題 (Write a thesis statement)
- 寫文章大綱 (Make an outline)
- 開始寫作 (Begin writing)
- 修改和編輯 (Revise and edit)
當然，在前面的步驟，我們都不用考慮句式多樣性，只需要在最後一步考慮就行。