Mongolian Students Acquisition Object Classes "Gei""Gen""Rang" Preposition Errors Analysis

Chinese is an isolated, Tibetan language, lacks of morphological changes in language, Chinese word formation consists of word roots, affixes (prefix, infix,suffix) The part of speech, one of the most commonly used, plays an important role is the preposition. Prepositions in Chinese grammar played a very important role, but the preposition does not have a concrete meaning, it represents an abstract syntax significance.Mongolian is the adhesion Altaic language, a language with huge morphological changes. Mongolian word formation consists of roots, affixes. Suffixes Mongolian languages does not have an infix and prefix, only have an suffix. Mongolian languages do not have prepositions, only using Mongolian semantic grid affixes correspond to the usage of Chinese prepositions. Therefore, the Mongolian students make prepositional mistakes while they are studying Chinese. There are many researchers have conducted research on prepositions, however, the study on object classes preposition error analysis is less. The author compares Chinese and Mongolian grammar, based on the theory of errors according to the relevant types and causes of errors were summarized, and makes some teaching suggestions.The paper first elaborated the selected topic significance and purpose of topics, and analyses the relevant research achievements of prepositions and prepositional errors, introduces the research ideas, research methods and research of this paper. The second chapter summarizes the Mongolian semantic cases compared with the Chinese prepositions. Chapter third suggests Mongolian students to learn prepositions\"for, like, let\" errors analysis of Mongolian students of the use of prepositions errors, according to the classification of preposition errors types, and according to the modern Chinese correct theory instruction, analyses the errors to correct. Chapter4 according to the preposition\"gen, gei,rang\" the types of errors cause and errors on the Chinese preposition teaching of Mongolian students put forward improvement Suggestions, mainly from the two aspects of teaching materials and teachers, to the Mongolian students in studying Chinese preposition in the process of teaching reference.