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and 2 of them call a flop bet on a board that is not at all drawy

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The call on the flop is going to be unpaired overs and/or stray aces the vast majority of the time. Anybody with a pair will be raising the flop, both to protect his small boat, and to find out how serious you are. The fact that you raised preflop and bet the flop, strongly weighs in favor of betting the turn.