Comparative Study On Prepositions "Zi(自)" "Cong(从)" " ZiCong(自从) "

This paper,on the basis of previous studies,from the diachronic and synchronic plane angles,makes a detailed description and comparison of the prepositions"zi(自)""cong(从)""zicong(自从)".Base on the search and investigation of corpus,we’ve classified and compared these three prepositions from the diachronic angle and found that they varies from each other in the frequency of use and in the grammatical evolution.Grammaticalization path of"zi(自)":the noun of human body organs>the pronoun refers to your own>the preposition means"starting point">the preposition means"to through".Grammaticalization path of"cong(从)":the verb means"to follow">the pronoun refer to your own>the preposition means"to through".Grammaticalization path of"zicong(自从)":the preposition"zi(自)"+the preposition"cong(从)">the preposition means"starting point".Differences in the frequency of use of these prepositions:in the ancient Chinese,"zi(自)"was used a lot;in modern Chinese,it was used less than"cong(从)";"zi cong(自从)"was least used.We have also applied such theories as the three-dimensional grammar and the frame structure to compare the preposition"zi(自)""cong(从)""zicong(自从)"from a synchronic point of view.We’ve found that they had several differences:First,their structures are different.The prepositional structure of"zi(自)"could be used not only as adverbials or attributives,but also as complements.Second,they represent different“starting point”time."zi(自)"and"cong(从)"could represent the past,the present and the future.When used,they are often followed"qi(起)""yilai(以来)""yihou(以后)"and"kaishi(开始)"to form a fixed frame."zi cong(自从)"only represents the past time and used after the words"yilai/hou(以来/后)",or to form behaviors and actions phrases.Third,these words are used in different occasions."cong(从)"is often used both in written and oral language,while"zi(自)""cong(从)"are ofen used in written language.Finally, based on the error analysis theory, we have conducted a survey from the perspective of teaching Chinese as a foreign language and found out that although foreign students cannot well distinguish the three words, students in gradethree do better, mostly because they have learned Chinese longer and reached a higher SHK lever. Meanwhile, we also discovered that the similarities between words and the time intervals of learning have an influence on the mastery of words.