入乡随俗 When in Rome, do as the Romans do.
Explanation: Conform to the manners and customs of those amongst whom you live.
Example: 到了法国就要吃西餐，这就叫入乡随俗

失之东隅，收之桑榆 What you lose on the swings you get back on the roundabouts.
Explanation:A rough way of starting a law of average; if you have bad luck on one day you have good on another; if one venture results in loss try a fresh one---it may succeed.
Example: 失之东隅,收之桑榆，我们都知道盲人的听觉、触觉都特别发达。这是为什么?原因在于盲人丧失视觉后,生存的需要促使其它感官...实现心理平衡,这被称为“补偿”