Said, "under"

The article discusses the characteristics of 下 as a noun locality,an adverbial word and a verb.It makes a set of terms of explaining for the meanings of F ,and shows clearly the relation between the meanings of 下.Depending on speech matierial,the author analyses the sentence patterns in which 下 is used.The author holds that the basic meaning of 下 as a noun locality should be divided into three branches of meaning,and a method which can be named "spraining" play an important role in the course of changing of F's usage.And the author also holds that the basic meaning of the verb 下 conclude three important branches of meaning.