In the past two decades researchers have explored several alternative strategies , from neural networks to general rules based on advice from expert players , with indifferent results 过去的二十年间，研究人员探究了若干种二选一策略，从神经网络到基于优秀选手的建议而建立的法则，但结果仍是一样。
46 , xuan haiyang used to be an excellent track field player , became director of the training department of the chinese tennis administrative center and leader of national tennis team after retired 46岁曾经是中国田径队的优秀选手。退役后调到中国网球协会训练部任部长，并担任中国国家网球队的领队。
