I bought bread, cheese, and pickles at the grocery store.
Astronomers have known about the positions of stars for centuries, but they didn’t understand that the earth revolves around the sun.
In preparation for the next convention, the representatives studied up on the most important issues.
All doctors, if they care about their patients, are concerned with good office hygiene.
Comma splice 不要在未使用連接詞的情況下，使用逗號分隔兩個獨立的從句
錯誤范例： Thousands of protesters showed up on the streets, they were shouting and carrying large posters.
正確范例： Thousands of protesters showed up on the streets; they were shouting and carrying large posters.
Combining lengthy phrases 在復合句中使用逗號或用逗號來分隔短句會造成讀者的困惑，這種情況應使用分號。
錯誤范例: Some useful subjects are English, which is an international language, math, which is used in all domains of sciences and social sciences, and philosophy, which underpins many other areas of study.
正確范例: Some useful subjects are English, which is an international language; math, which is used in all sciences and social sciences; and philosophy, which underpins many other areas of study.
冒號來條列下文，并告訴讀者 “Here’s what I mean.”。通常在英文寫作中，冒號不常被使用，除非您有許多內容需要列舉，冒號的使用準則較為嚴謹，但也相對容易被記住。
Humans use five major senses: sight, hearing, smell, taste, and touch.
Martha realized that her worst fear was coming true: her son was being sent to war.
(*冒號后用獨立的從句解釋 Martha’s fear)
To the Central Valley Committee Chairman:
冒號后的第一個字母不要大寫，除非是專有名詞， is part of a quote, or is the first in a series of sentences:
錯誤范例: I have three desires: To eat, sleep, and work.
正確范例 : I have three desires: to eat, sleep, and work.
In Chapter 3, the author explains his theory: “Dogs have dreams, but they don’t dream as humans do. Their dreams reflect a primal desire for pleasure, whereas humans are preoccupied with the ego and self-image. This is equally true in wakefulness and sleep.”
There is one mantra that can sum up our position towards climate change: urgent action.
錯誤范例: Sarah and her friends loved spending time on the mountain : nature always held a special meaning for them.
正確范例: Sarah and her friends loved spending time on the mountain ; nature always held a special meaning for them.
The universe has always called to human beings; there could be no more final frontier than space.
Sam thought David was inviting him to the picnic to enjoy a nice day out; as it turned out, David was planning a surprise birthday party.
Our family members came all the way from Denver, Colorado; Rochester, Minnesota; and even Paris, France.
My main research objective is to isolate the cause of the disease, as well as to contribute to the existing literature; for this will bring an end to starvation across the continent, create new study designs related to epidemiology, and change the very paradigm of my research field.
錯誤范例: The specimens were treated properly, however, they were not stored properly.
正確范例: The specimens were treated properly; however, they were not stored properly.
*副詞“however”表示的是連接兩個獨立的從句； 不要用逗號去連接兩個不包含并列連詞(and, but, or, nor 等等)的獨立從句。
錯誤范例: The sun is wonderful: it produces light, which plants need to survive, it gives us warmth, which is useful for most life, and it makes a sad day happier, which is obviously a positive trait!
正確范例: The sun is wonderful: it produces light, which plants need to survive; it gives us warmth, which is useful for most life; and it makes a sad day happier, which is obviously a positive trait!