abstract class allmethod //模板
    {
      public  abstract void testA();
       public abstract string testB();
        public abstract void getkey(string temp);
        public void showmethod() 
        {
            testA();
            testB();
           getkey(testB());
        }
    }
 class imp : allmethod //方法实现
    {
        public override void testA()
        {
            Console.WriteLine("如果你是帅就输入a");
        }        public  override  string testB()
        {
             string temp=Console.ReadLine();
            
            return  temp;            
        }
        public override  void getkey(string test)
        {            Console.WriteLine(test);
            if (test.Equals("a"))
            {
                Console.WriteLine("不要脸");
            }
            else
            {
                Console.WriteLine("你确实丑");
            }
            
        }
    class Program
    {
        static void Main(string[] args)
        {
            allmethod op = new imp();
            op.showmethod();
        }
    }
问题:
当我输入a时
却依然无法正常打印
跟踪testB()为空
why?