3 Never use a verb other than "said" to carry dialogue. The line of dialogue belongs to the character; the verb is the writer sticking his nose in. But "said" is far less intrusive than "grumbled", "gasped", "cautioned", "lied". I once noticed Mary McCarthy ending a line of dialogue with "she asseverated" and had to stop reading and go to the dictionary.
4 Never use an adverb to modify the verb "said" . . . he admonished gravely. To use an adverb this way (or almost any way) is a mortal sin. The writer is now exposing himself in earnest, using a word that distracts and can interrupt the rhythm of the exchange. I have a character in one of my books tell how she used to write historical romances "full of rape and adverbs".
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