import static mytools.Print.*;
class Sports{
    void play(){
        print("super play");
    }
}
class Football extends Sports{
    void play(){
        print("足球是用脚踢的！");
    }
}
class Bascketball extends Sports{
    void play(){
        print("篮球是用手打的！");
    }
}
public class Test2{
    static void howToPlay(Sports sp){
        sp.play();
    }
    public static void main(String[] args){
        howToPlay(new Football());
        howToPlay(new Bascketball());
    }
}

------解决方案--------------------
基本正确，但最后将超类改成抽象类，如：
public   class   Sports{
public  abstract  void   play();
}

------解决方案--------------------
没大懂你的意图
Java code

public class TestSports {
    public   void   howToPlay(Sports   sp){ 
        sp.play();
    }

    public static void main(String[] args){
        Sports football=new FootBall();
        Sports basketball=new Basketball();
        TestSports test=new TestSports();
        test.howToPlay(football);
        test.howToPlay(basketball);
    }
}
 class Sports {
    public void play(){
        System.out.println("sports!");
    }
}

 class FootBall extends Sports{
     public void play(){
         System.out.println("kicking a goal!");
     }
 }
 
 class Basketball extends Sports{
     public void play(){
         System.out.println("give a 3-p shot!");
     }
 }

------解决方案--------------------
嘿嘿，一天登录一次（或者100次）就可以增加10分可用分的。