Parentheses

( ) These are also called round brackets.

Parentheses are the marks which show that something is not really important but is still worth mentioning. Parentheses can also be used when there’s information which should be given, but it’s not enough to have its own sentence. When reading aloud, the reader will naturally lower their voice and tilt their head a little, showing that this parenthetical information is a comment being made to the side.

It’s a bad idea to use double brackets (brackets inside brackets). If you absolutely must use double brackets, use two sets of round brackets. Don’t mix-and-match different shapes of brackets (that’s only done in mathematics).

We (Anna, Michael and I) have decided to volunteer for four hours each week, somewhere in the community.

The song Forever Young (Alphaville’s version, not Jay Z’s) has been playing in my head for several hours now.

While walking down the street (paying more attention to her music that to her feet), Catherine tripped over the curb and sprained her ankle.

The cat was sleeping (did you expect anything different?) and was shocked awake when the fire alarm went off.

Unless you’re writing informally, as in the last sentence, final punctuation is not likely to be found inside the parentheses.