Work consists of whatever a body is obliged to do, and play consists of whatever a body is not obliged to do.

Work consists of whatever a body is obliged to do, and play consists of whatever a body is not obliged to do.

工作是由一个人必须做的事情组成的，玩耍是由一个人没有义务做的事情组成的。

-- Mark Twain 马克·吐温