【正文】        Abstract: Cohesion and coherence are two basic concepts in the field of discourse analysis, and they are also very prominent terms in discourse analysis and text linguistics. This paper first classifies the definition of cohesion and coherence and the relationship between them. Then this paper analyses the cohesive devices, and at last this paper also analyses one radio interview with the cohesive devices.
        Key Words: Discourse; Cohesion; Coherence; Cohesive Devices; Interview
        1. Introduction
        Cohesion and coherence are the most important concepts in discourse analysis (Dong, 2005). Discourse analysis is an investigation into approaches to discourse coherence (Halliday & Hasan, 1976,1984). Stubbs(1983:126) found that cohesion has to do with relations between surface linguistic forms; whereas coherence refers to relations between communicative acts”. Wales(1998:134) defined cohesion as “textual coherence” and coherence as “semantic cohesion”. Within the discourse, the analysis of cohesive ties shows us how we as readers or writers use linguistic signals to promote cohesion. 
        Cohesion is to identify the linguistic features that cause the sentence to “cohere”─ something that happens whenever the interpretation of one feature is dependent upon another elsewhere in the sequence. Within the discourse, the analysis of cohesive ties shows us how we as readers or writers use linguistic signals to promote cohesion. Cohesive links go a long way towards explaining how the sentences of a text hang together, but they do not tell the whole story.
        2. Analysis and Discussion
        Cohesive devices, formal links between sentences and between clauses, are used to tie pieces of text together in specific ways. A number of grammarians have drawn up a list of the various kinds of cohesive links to be found in texts. Halliday and Hasan’s system distinguishes five major types of grammatical cohesive ties: reference, substitution, ellipsis, conjunction, and lexical ties. 
        (1) Reference
        The first major kind of cohesion is known as reference cohesion (Crystal,1997:119). There are three types of relationship: ① anaphoric relations, looking backwards for their interpretation ② cataphoric relations, looking forwards ③exophoric relations, looking outward.
　　In the interview “the great majority of the people of the British people do want to see a United Europe. They want to see all these obstacles removed. They don't want to have customs and permits and all the rest of it”, the third person pronouns ‘they’ refers to ‘the great majority of the people’, and that is anaphoric relations. And ‘it’ refers to ‘we have one currency’, which is cataphoric relations. From this we could know, reference could use brief reference forms to express the context which has appeared or will appear in order to have the effect of the simple discourse rhetoric. More importantly, reference can make the discourse more compactly in structure to be an integral whole.
        (2) Ellipsis
　　A part of a subsequent sentence which would repeat a phrase or idea explicitly stated in preceding sentence is omitted, making the second sentence depend for its completeness on the first. Fowler (1998:63) points out that ellipsis is a very important cohesive device in dialogue, a guarantee that speakers are concentrating together on a single topic and on the background knowledge relevant to the topic. At the end of the interview, “Int: And you think they will? EH: Oh, no doubt about that at all. Absolutely no doubt.” The auxiliary ‘do’ is omitted in the first sentence. 
        (3) Conjunction
        As McCarthy(1991:46) suggests, it is somewhat different from reference, substitution and ellipsis. A conjunction does not set off a search backward or forward for its referent, but it does presuppose a textual sequence, and signals a relationship between segments of the discourse.
        a. Additive: A succeeding sentence supplies some additional information about a topic. In the interview, the conjunction word ‘and’ connects two coordinate clauses and phrases to express additive relationship. 
　　b. Causal: once again they may or may not be stated explicitly in a conjunction.
　　In the sentence “Let's just talk for a moment about our relations with the European Community because it's very nearly fifteen years now”, the word ‘because’ is causal conjunction. Although the reason comes after the result, the logical relationship is very clear.
　　3. Conclusion
　　Cohesion and coherence are the essence of the discourse analysis, and cohesion and coherence are two important terms in the study of discourse and a major topic of discourse analysis. This paper mainly analyses the radio interview from the perspective of cohesion and coherence and cohesive devices. With the help of the cohesive devices, such as reference, ellipsis and conjunction, the radio interview could become more coherent. And we could use very simple and brief expressions to express the writers’ meaning to make the discourse more coherent and cohesive.
 　References:
  [1]Crystal, D. 1997. The Cambridge Encyclopedia of Language. 2nd Edition. Cambridge: Cambridge University Press.
  [2]Dong, S. R. 2005. Discourse Functions of Metaphor. Master thesis, Shandong University, Jinan, China.
　　[3]Fowler, R. 1986. Linguistic Criticism. Oxford: Oxford University Press.