The article discusses controversial points of a linguistic concept of parts of a sentence in Chinese with the special attention to the case of complement (补语 bǔyǔ). The task of distinguishing grammatical units of a sentence that share one syntactic function is considered. The article analyses structural and semantic features of the units that perform the role of complement in a sentence, as well as discusses the criteria for distinguishing it from other parts of a sentence, i.e. from an object and adverbial modifier.