A good referee not only knows the basketball rule thoroughly but also realizes the meanings and spirits for the games. He can make the judgements of violation and foul identically fit the advantageous and disadvantageous principles. Under the slight and non-advantageous conditions, the principles should be used and especially have to be carefully judged which one must execute and which one can reject and forgive. This kind of instantaneous determination wholly depends on the executive measure of the referees.