Single quotation marks are used to mark quotations within quotations.
In American writing, the practice is to mark the beginning and ending of quoted words, phrases or sentences with double quotation marks and to use single quotation marks for quotations within quoted material. For example:
- "I am sure that he said, 'I'll do it on the way,' just before he left," she replied.
- "Please stand as we begin our evening with that classic by Katherine Lee Bates, 'America The Beautiful,''" he said.
- "I think that the subject used 'I don't understand the question,' a little too often," observed the officer slowly.
In American writing, the comma or period should be placed inside the quotation mark. If both single and double quotation marks are used at the end of a sentence, the period falls should be placed within both sets of marks. Where question marks and exclamation points are placed depends on the meaning.
The British practice is often the reverse of the American practice. In British writing, single quotation marks are often used to mark the beginning and end of quoted material, whereas double quotation marks are used to mark quotations within the quoted material.