英语小笑话:I'm not having it all cut off 没把头发全剪掉啊

I'm not having it all cut off 　没把头发全剪掉啊
　　Miles sometime went to the barber's during working hours to have his hair cut. But this was against the office rules: clerks had to have their hair cut in their own time. While Miles was at the barber's one day, the manager of the office came in by chance to have his own hair cut and sat just beside him.
　　"Hello, Miles," the manager said. "I see that you are having your hair cut in office time."
　　"Yes, sir, I am," admitted Miles calmly. "You see, sir, it grows in office time."
　　"Not all of it," said the manager at once. "Some of it grows in your own time."
　　"Yes, sir, that's quite true." Answered Miles politely, "but I'm not having it all cut off."