abstract Many scholars discusses the topic of Chineses adverbs [zài] and[ yòu].My thesis focuses on the collocations of these two morphemes. I explains their collocations and classifies by their main meanings. It is generally recognized [yòu] occurs in realis contexts,and [zài] appears in irrealis ones. I consider more situations except realis and irrealis. I give these two morphemes more clarify environment.