在直接引用某人说过的话时，会用到引号。但如果是转述某人说过的话，就不用引号。
举例
- "i'm going to the store now," she said.
- harry told me, "don't forget your soccer jersey."
- harry told me not to forget my soccer jersey.
如果要在引用句中再引用他人的话语，就会用单引号和双引号来区别两句引文。
举例
'i haven't spoken to peter for months,' dianne said.'the last time i spoke to him he said, "i'm going to bahrain and won't be back for about three years", i've heard nothing since then'.
用单引号或双引号来表示谚语或不熟悉的说法
举例
- i've always thought that he was very annoying, a bit of a 'pain in the neck.'
- i'm not sure what you mean by "custodial care", but i'm sure you will explain it to me.
在学术写作上，会用单引号或双引号来标明文献或资料来源。文献引用书写格式有好几种，学术机构一般会有偏好的一种写法，他们有时会在网站或简章上公布指定的格式。
举例
- "the migration flight of the lesser tweazle", by jeremey adams, the bird spotter magazine, july 2009.