Courtesy costs nothing. Lower the toilet seat after use. Let the people in the elevator exit before you enter. Return shopping carts to their designated areas. When you borrow something， return it better shape (filled up， cleaned) than when you got it.
礼貌，并不需要花钱。用完马桶后，把马桶盖放下；上电梯时，耐心等别人出来再进去；把购物车放回指定区域；在借东西时，归还时要东西的状态要比你借的时候还要好（例如给车加满油、把物品清理干净）。
Time is the invisible material in all my works.
统计学家不能推卸理清科学推断原理的责任，同样，任何其他思考者也必须承担类似的义务。
希望不是一种感觉，而是一种可行的、戏剧性的行动。
Small changes can have big effects when they help people break out of the poverty trap.