用python编程，定义一个学生类，创建两个学生对象，实现二人关于学习体能唱歌的对话。

好的，以下是Python代码实现：

class Student:
    def __init__(self, name):
        self.name = name
    
    def learn(self):
        print(f"{self.name} is studying hard.")
    
    def exercise(self):
        print(f"{self.name} is exercising to keep fit.")
    
    def sing(self):
        print(f"{self.name} is singing a song.")
        
# 创建两个学生对象
student1 = Student("Tom")
student2 = Student("Jerry")

# 实现二人关于学习，体能，唱歌的对话
student1.learn()
student2.learn()

student1.exercise()
student2.exercise()

student1.sing()
student2.sing()

输出结果：

Tom is studying hard.
Jerry is studying hard.
Tom is exercising to keep fit.
Jerry is exercising to keep fit.
Tom is singing a song.
Jerry is singing a song.