要么忙着活，要么忙着死，人只有两种选择。

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.

市场组合是所有投资者都应该持有的唯一组合。