parentheses

   Parenthetical matter can be thought of as any information so incidental to the main thought that it needs to be separated from the sentence that contains it. It can be set off with dashes, brackets (usually reserved for explanatory insertions in quotations), commas, or, of course, parentheses. It is, in short, an insertion and has no grammatical effect on the sentence in which it appears. It is rather as if the sentence does not even know it is there. Thus this statement from The Times is incorrect: "But that is not how Mrs. Graham (and her father before her) have made a success of the Washington Post." The verb should be has.

   While the parenthetical expression has no grammatical effect on the sentence in which it appears, the sentence does influence the parentheses. Consider this extract from the Los Angeles Times (which, although it uses dashes, could equally have employed parentheses): "One reason for the dearth of Japanese-American politicians is that no Japanese immigrants were allowed to become citizens-and thus could not vote- until 1952." As written the sentence is telling us that "no Japanese citizens could not vote." Delete could not.

   When a parenthetical comment is part of a larger sentence, the period should appear after the second parenthesis (as here). (But when the entire sentence is parenthetical, as here, the period should appear inside the final parenthesis.)