The Editor's Manual
Free learning resource on English grammar, punctuation, usage, and style.
Use “sic” to indicate a grammatical or spelling mistake in the original text of a quote. “Sic” is generally italicized in formal texts. Also enclose “sic” in brackets in formal writing.
Adverbs modify adjectives, verbs, other adverbs, phrases, clauses, or entire sentences. They express a relationship of manner (how), time (when), place (where), duration (how long), degree (how much), circumstance, and connection (why, whether).