Where Does the Period Go?
If an entire sentence or group of sentences appears in parentheses, then put the period inside the closing parenthesis. This is a parenthetical sentence. Thus:
Parenthetically Enclosed Sentence
Her mind was clouded. (She hadn't thought of him in years.) But she shook it off and continued down the hill.
If parenthetically enclosed words end a sentence, then the period comes outside the closing parenthesis:
Parenthetical Words Ending the Sentence
He enjoyed all kinds of fruit (especially apples, oranges, and bananas).