礼尚往来（禮尚往來）　

◎ 礼尚往来 lǐshàngwǎnglái

[courtesy demands reciprocity; deal with sb. as he deals with you; pay sb. back in his own coin] 在礼节上注重有来有往,借指用对方对待自己的态度和方式去对待对方

礼尚往来,往而不来,非礼也;来而不往,亦非礼也。——《礼记·曲礼上》