谓人或事物变化无常,分合无定。 -----------------国语辞典:世事变化无常,分合无定。《三国演义.第一回》:「话说天下大势,分久必合,合久必分。」英语 lit. that which is long divided must unify, and that which is long unified must divide (idiom, from 三國演義|三国演义[San1 guo2 Yan3 yi4]), fig. things are constantly changing