It sometimes sounds better to phrase "I don't know" along the lines of, "Let me check on that and get back to you." In Navy ROTC 'boot camp,' it was verboten t

It sometimes sounds better to phrase "I don't know" along the lines of, "Let me check on that and get back to you." In Navy ROTC 'boot camp,' it was verboten to respond "I don't know"; the only acceptable phrasing was "I'll find out, sir." (And the cadre followed up to make sure we did find out.)