饱暖非天降,赖尔筋与力。
衣服和食物不是天上掉下来的,是通过辛勤劳动换来的。
The P versus NP problem is one of the most important problems in computer science.
Don't try to win a friend by presenting gifts。You should instead contribute your sincere love and learn how to win others 'heart through appropriate ways.