Smile, how warm the word is! It can make anyone happy. It's not like anything  else, but just warm, makes you feel warm. Mother's smile is like a spring wind. It is so gentle. When you are sad, _ can make you happy again. When you fail to do something, it can make you stand up and work again. When you give up  doing something, it can make you try your best again... Smile, so easy, but also so useful. Let's learn to smile. Everyone needs others' smile. When we give others a smile, we will feel happy, too. And maybe next time, when you need a smile, the others will give it to you. Let's learn to smile often. I believe it can even make the whole world warm. Living with a smile, every day will be sunshine. Which of the following is right?
Smiling is difficult. Smiling is serious. Smiling is helpful. We can't smile often.