kinglongyy

Teacher：“I have two questions，it isn't necessary to answer the second question if you know the result of the first question．How much hair do you have？”
老师：我有两个问题，如果你知道第一题的答案的话，你就不必要回答第二个问题。你有多少头发？
Student ：“A hundred and twenty millions．”
学生：1.2亿
Teacher：“How do you know it？”
老师：你怎么知道的？
Student：“It is not necessary to answer the second question．”
学生：我不必要回答第二个问题