| The "ba" sentence in modern Chinese has close relationship with the unmarked patient-as-the-subject sentence. Syntax aspect analyzes and compares the two kinds of sentences of subject, predicate and object. Study finds that most subjects of "ba" sentences are people while the subjects of unmarked patient-as-the-subject sentences are basically things. Psychological verbs, such as "zhidao","mingbai" can appear in unmarked patient-as-the-subject sentence, but can not appear in "ba" sentence. The sentences with object after the predicate are not common use of the two. Semantic aspect discusses semantic roles. Study finds the agents in "ba" sentences appear at the beginning of the sentences, used as subjects. While the agents in unmarked patient-as-the-subject sentences usually don’t appear at the beginning of the sentences and are not used as subjects. Construction comparison study shows the semantic of constructions and draws the semantic pictures of the constructions. Pragmatic part commences from information arrangement and discourse adaptability. In most cases, the part before predicate is known information, and the predicate is unknown information."Ba" sentences are mostly used in written language while unmarked patient-as-the-subject sentences are often used in spoken language. The paper also studies the conditions for the two to convert and analyzes the reason why the two can or can not convert. |