世界所有前进的动力都归功于不安分的人;幸福的人不可避免地把自己局限在古老的界限内。
The world owes all its onward impulses to men ill at ease; the happy man inevitably confines himself within ancient limits.
你送给我桃子,我就回报给你李子。意思是做人要知恩图报,不能忘恩负义。也比喻礼尚往来,相互赠送礼物。
The past is always tense, the future perfect.