| In the teaching of Chinese as a foreign language,how to teach and how to study conjunctions have always been difficult,"er" as a conjunctions which is used frequently and widely,especially the most important.The research on the application of "er" in ancient Chinese has gained a lot of achievements,but the research of "er" in the study of modern Chinese ontology and the teaching of Chinese teaching as foreign languages is still very deficient.Considering that English is the most widely used language in the world,this paper selects learners from seven countries with English as their mother tongue or official language.This article combines the errors analysis and comparative analysis.First,this paper sums up the "er" corpus of foreign students’ composition in Beijing language and culture university HSK dynamic corpus,from "false addition,addition,omission,fault sequence"four directions.on the basis of the types of errors,this paper analyses the causes of errors and teaching Suggestions.Second,it makes a comparative analysis of "and" and"er",to analyzes the similarities and differences of the two words from three perspectives.In order to guide the teaching and learning of other conjunctions,we hope to combine the two methods of analysis and comparative analysis to obtain the experience and weak points of learners’ "er".This paper is divided into five parts.The first part is the introduction.This paper briefly introduces the reasons,research contents,theoretical basis and "er" research overview of this paper.Research overview mainly summarizes the meanings in the dictionary,The ontological research of "er" in ancient Chinese and modern Chinese is analyzed from two perspectives,the research on the teaching of Chinese as a foreign language.In the second part,by means of the theory of intermediary language and the theory of bias analysis,this paper analyzes the types of errors in the "er" errors,including"omission,adding,misadding and misordering".At the same time,the causes of bias are analyzed from both external and internal directions,and countermeasures are put forward.The third part.compare "and"and "er" from three aspects in both the sentence and the sentence:we both have,you have but me do not have,and I have but you do not have.The fourth part discusses the teaching strategies of "and" from the three aspects of learner,textbook and dictionary and classroom teaching.The fifth part is the conclusion.This part summarizes the research results in this paper,points out the problems in this paper,and forecasts the future research. |