按照“‘是’字句是有‘是’字做标记的句子”的定义,我们发现汉语方言中的“是”可以是存在动词、时间副词、时处介词和语气词。在湘南土话、吴语、徽语、客家话中都存在这种现象。“是”的这些“特殊”用法从表判断的“是”发展而来,其中表时处所的介词是由“是”表示“存在”义虚化而来,与普通话“在”的虚化路线大体一致。 According to the definition that ’’ yes ’’ is a sentence marked with ’yes’, we find that “yes ” in Chinese dialects can be verbs, adverbs of time, prepositions and mood words. In southern Hunan dialect, Wu, Hui, Hakka dialect exists in this phenomenon. These “special ” usage of “is ” evolved from the “yes ” of the table, where the preposition of the place is represented by “yes ” meaning “existence ” , And Putonghua “in ” the virtual line generally consistent.