Possessives Comparatives Cross References See also General Conventions Grammar Use standard grammar, punctuation, and spelling. Although published documents are edited and proofread, not all errors get caught, and such errors distract readers from the content of the writing. Authors of documents should do the first proofreading.
Punctuation Here are a few notes about punctuation conventions.
Sometimes you should add a comma before an afterthought, as in this case. In a series like the one in this sentence, use a comma after the first item, after subsequent items, and before the final item. The magnetic tape that you sent us is unreadable. The magnetic tape, which you sent us, is unreadable. In general, use a semicolon only where you can use a period.