What do you konw about smile?When i was a kid,i always thought smile is just a way to express what you're feeling at that moment.But now,i know smile is not only a face but also a way to change the world. Smile also changes the world.When you give your friend a smile,she might feel the deep ture friendship between you and her.When you give your parents a smile,they might feel the love that you give back to them.When you give a stanger a smile,the warm feeling is going through her or his heart. If you want the world to be nice,learn to smile yourself!!