第一题 package net.mindview.polymorphism; //基类-自行车 class Cycle{ } //子类-单轮车 class Unicycle extends Cycle{ } //子类-双轮车 class Bicycle extends Cycle{ } //子类-三轮车 class Tricycle extends Cycle{ } public class CycleCompetition { public static void ride(Cycle cyc…