John is a very strong man. He gets a job of cutting  trees in a forest. His boss gives him an axe and showed him the area where he should work. The first day, John cuts down 18 trees. "Good," the boss says, "keep it up!" happily, John  tries harder the next day, but he only cuts down 15 trees. The third day he tries even harder, but he can only cut down 10 trees. Day after day he cuts down fewer and fewer trees. "I must be losing my strength ," John thinks. He goes to the boss to say sorry and says that he can not know what is going on. "When is the last time you sharpen  your axe?"  the boss asks. "I'm busy cutting trees, so I have no time to do _ . " The moral of this story: While John is working hard, he doesn't work "smart". He doesn't think about the best way to do his job. Why does John cut down fewer and fewer trees day after day?
Because he is losing his strength Because he is busy doing something Because he doesn't sharpen his axe. Because his boss lets him do so.