| The cohesions of oral discourse can include both lexical methods and sentence collusion. Lexical method can be divided into the cohesive devices and cohesive form, while the former includes the usage of logical words and referring vocabulary and the latter includes the reproduction and cooccurrence of the same words. The sentence collusion can be divided into the sentence structures of collusion sentence, affirmative-negative sentence and loop sentence.Through the investigation of the oral research of primary, intermediate and advanced level foreign students, the feature of the lexical cohesion can be divided into the following factors:1. The frequency of occurences of lexical words of cause and result, adversative, parallel and assumptions is much higher than that of conditions, objectives and concessions. Condition and concession oral discourses are difficult to acquire. And the errors of conditions, relationships and concession sentences are reducing with the increasing language levels.2. The trend of referring words usage amount will be "personal reference> personnel allegation> space allegation> text allegation> time allegation". And the personal reference trend will be "third person> first person> second person". Furthermore, the usage of "This" is almost twice as "That", since foreign students tend to use the words which is more closed to their mental distance.3. The frequency of the reproduction words including underlying words repetition,synonym repetition, hyponymy repetition and notional words repetition in different levels reveals basically the same tendency. The error rate is falling and foreign students can correct the error in a more efficient way.4. The trend of five forms of word cooccurrenceis "antisense relationship> mix and match relationship> the whole and part of the relationship>the next relationship>the sequence relationship". And the feature of sentence collusion can be the following factors:1. The usage of sentence structure which is followed by the former is more used than that invokes the latter in all levels.2. The error among the negation language in primary level is mainly the words overlapping problem. Sentence structural hybirdity and information redundancy are the most common errors in middle level.While in advanced level the misusage of reverse semantic exists more frequently.3. Words thimbles are more than sentences thimbles in different levels.The majority errors will be that the words replace the phases. According to the investigation of lexical cohesion and sentence collusion and the analysis of their characteristics, the thesis proposes several suggestions for international students teaching:1. To develop the lexical cohesion ability, teachers should focus on the teaching strategies of the usages for conjunctions, logic words, temporal words and place words, repeated words and referred words.2. The development of sentence collusion should be focused on the analysis of the complete frame and the hint of the words. And students need to develop an ability to identify the type of the discourse and construct a complete frame(extending and outwarding). In addition, the students’ sensibility of aiming trend and dealing of the first and last sentences should be strengthened. |