Parentheses enclose material that is an interruption of the text but adds information.
- The park (in Washington) is always crowded in summer.
- I know the answer (I think) to the final question.
If the material enclosed falls at the end of a sentence, the end mark is placed outside the closing parenthesis. If the material is a complete sentence within itself, the end mark is placed inside the closing parenthesis.
- We provide a complete list of stores (see our website).
- We provide a complete list of stores. (See our website.)
Use brackets to enclose additions to quoted material. These additions, made by editors or writers, usually clarify or comment on the material.
- “Mark Twain said it [the river] taught him all he ever knew about life.”
- “Virginia Woolf lived with him [Lytton Strachey] while recovering from her illness.”
- “There were few Esquimouxs [sic] living in the region we explored.”
Brackets are also used to enclose material that falls within material already enclosed by parentheses.
- The fall sales records are encouraging (see page 33, Monthly Sales [Table 2.1] for a detailed breakdown by product line).