The vast majority of focus-sensitive operators in Chinese are adverbs, and there are some floating in word order. We take these focus-sensitive operators as the focusing adverbs. This thesis mainly examines the source of the structure lian... dou..., firstly it studies stress and semantic direction of the lian...dou… sturcture; secondly, it studies the function of lian as a focal mark and dou as a focus-sensitive operator.