A,Brief,Overview,of,Cohesion,in,Text|in terms of

　　Abstract：In a text, there are many ties used to link the language together. Cohesion and coherence are the two important factors. In order to create the coherence in the discourse, writers and speakers have to use a lot of cohesive devices within clause and between clause complexes, including reference, ellipsis, substitution andlexical cohesion. The analysis of cohesion facilitates the use of language.
　　Key words：cohesion coherence text
　　
　　Ⅰ Introduction
　　The word TEXT is used in linguistics to refer to any passage, spoken or written, of whatever length, that does form a unified whole（Halliday & Hasan：1976）. Readers and hearers could find out whether the passage is meaningful，which has a unified construction, or it is just a set of unrelated words and sentences. All texts possess the property of texture. Writers and speakers would consciously try to create the coherence in text with a lot of cohesive markers. Cohesion and coherence are crucial features for the text.
　　In 1976, Halliday and Hasan firstly proposed the concept of cohesion in Cohesion in English. They said that the concept of cohesion is a semantic one; it refers to relations of meaning that exist within the text, and that define it as a text [Halliday & Hasan: 1976]. Then a number of researchers began to turn their eyes to the study of cohesion in text, and to develop the theory given by Halliday and Hasan. Later, Thompson also gave his definition of cohesion. He suggested that cohesion refers to the linguistic devices by which the speaker can signal the experiential and interpersonal coherence of the text, and is thus a textual phenomenon [Thompson: 2005]. It is clear that in one way, cohesion is a semantic term, which establishes a unified meaning in the text; on the other hand, it is a set of word forms used to link one sentence with the other. No matter in writing or speaking, people would like to use a great deal of cohesive markers to unify the passage. They intend to construct coherence in meaning. Readers and hearers always assume coherence in discourse. Van Dijk has ever said that the notion of connectedness apparently covers one aspect of discourse coherence, viz the immediate, pairwise relations between subsequent proposition taken as whole" [Van Dijk:1980]. There is no doubt cohesion is the most important linguistic resource in constructing coherent meaning.
　　Ⅱ How to Be Cohesive in Text
　　In order to produce meaningful discourse, it is important to establish relations within clause and between clause complexes. In English, we often use markers like pronoun, demonstratives and repetition to construct the relations of meaning. According to Halliday, there are four kinds of cohesive devices used to create coherence in the text: reference, ellipsis, conjunction and lexical cohesion.
　　2.1 Reference
　　Reference is the set of grammatical resources which allow speakers to indicate whether something else in the text, or whether it has not yet appeared in the text [Thompson: 2005]. In other words, people use grammatical forms, including the third-person personal pronoun and the demonstratives, to refer to something that has been mentioned before or that will be talked about in the following. We could divide reference into two categories: exophoric reference and endophoric reference.
　　1)Exophoric Reference: It is used to link the language to the external world. When we have a conversation with others, it is often for us to take advantage of body language, which helps the comprehension of hearers; or we often apply reference into the text without mentioning the subject before because we presuppose our audiences could understand it according to the common knowledge and experience about the world.
　　2)Endophoric Reference: It is used to indicate how each clause or clause complex fits into each other. A passage with a lot of repetitions of the same word would seem to be odd and dull, even though it is also a kind of cohesive markers in the text.
　　2.2 Ellipsis
　　To avoid the repetition of those lengthy and unnecessary wordings, people often omit some parts in the sentence. The content of the missing part could be found in the previous. Such kind of cohesive devices doesn"t influence hearers" understanding. But unlike reference, ellipsis could only happen between adjacent clauses.Ellipsis proper and substitution are the main types of ellipsis.
　　1)Ellipsis Proper: In the place of ellipsis proper, the missing content could be filled in according to the preceding clause. It mainly happens in verbal form rather than in written form. In daily conversations, people usually exploit ellipsis proper to shorten their wordings. And that would not become uninterpretable to participants.
　　2)Substitution: It is a means to replace the main idea with one item in the place where the repetition would be done. Substitution, like so, neither, nor etc., is a grammatical term, implying a relation in the wording, while reference is a semantic term that indicates the relationship in the meaning. For example, the pronoun he for reference points to someone who has been talked about in the text; but the substitution one could be used to refer to the thing which just has the same feature as that mentioned previously. In addition, a referent item can refer to everything that has been mentioned in the text. But substitution is confined to the adjacent clause. Sometimes when it is used to substitute for the residue, it forms its own grammar as well.
　　2.3 Conjunction
　　Language users often exploit a lot of conjunctive items consciously both in spoken language and written language in order to make their wording logical. In the long stretch of text, conjunction plays an important role in how to combine clauses and clause complexes together to form a coherent text. As we know, there are many kinds of conjunction. In the following, it would give some common examples of conjunctive devices from A University Grammar of English:
　　Enumerative: first(ly), second(ly), third(ly); for one thing for another ; to begin with; in the first place; next; then; finally
　　Reinforcing: also; furthermore; moreover; in addition; what"s more
　　Apposition: in other words; for instance; for example; that"s to say
　　Result: consequently; hence; so; therefore; as a result
　　Concessive: anyhow; anyway; besides; however; nevertheless; though; yet; after all
　　Temporal Transition: meanwhile, meantime
　　In a word, conjunctive items are essential to set up relations between clauses. They help a lot to construct coherence in text.
　　2.4 Lexical Cohesion
　　It is impossible for people to change their topic from time to time. They would like to talk
　　about something along one systematic line. In order to maintain the passage as a whole and emphasize the main idea, people often have to repeat the key words again and again. They need to spend some time choosing words to make sure the continuity of the text. But there is no need for them to repeat totally the same words. They could reiterate the word with its synonym, superordinate or general word.
　　Ⅲ An Analysis of Cohesion in a text
　　As we know, many ties are used to form the text. Within clauses and between clause complexes, cohesive devices are the most important tools in creating coherence in the text. However, some forms of cohesion are easy to be observed. And their presupposed elements are explicit, which locate immediately in the preceding sentence. But for the others, their presupposed elements might place elsewhere. We could find them far back to the earlier clause, or we could not find them in the text but in the external world. In the following, I would like to give a simple example of the analysis of cohesion in a text. Here is a passage extracted from Reading for Pleasure:
　　The first thing I want to insist on is that reading should be enjoyable (1). Of course, there are many books that we all have to read, either to pass examinations or to acquire information, from which it is impossible to extract enjoyment (2). We are reading them for instruction, and the best we can hope is that our need for it will enable us to get through them without tedium(3). Such books we read with resignation rather than with alacrity (4). But that is not the sort of reading I have in mind (5). The books I shall mention in due course will help you neither to get a degree nor to earn your living, they will not teach you to sail a boat or get a stalled motor to run, but they will help you to live more fully (6). That, however, they cannot do unless you enjoy reading them (7).―W. Somerset Maugham.
　　Firstly, in sentence (3), the two them both refer to books that information in sentence (2); the it refers to instruction within the same sentence. Similarly, all the they and them in sentence (6) and (7) refer to the books I shall mention in due course in the sentence (6). We could see that all the presupposed elements of reference in this passage could be found within the same sentence or in the preceding sentence. It is easy for readers to understand the main idea in the text.
　　Secondly, let"s have a look at the reference such in sentence (4) and that in sentence (5). Both of them don"t simply refer to something mentioned right before it. But they include a much wider range of meaning. Each reference refers to the kind of books discussed in the first few sentences. In addition, we also found the exophoric reference in this passage, such as we and you.
　　Thirdly, the conjunctive items in the text are explicit. We first discuss the conjunction between sentences: The first thing Of course But . As it is shown, in the beginning of the sentence (5), we use concessive form but to indicate the change of the subject. The first few sentences are constructed to talk about the books being read without enjoyment. But to begin with the sentence (5), we turn to talk about the books which would cause our feeling of pleasure. Except for that, the conjunction within the clause is also explicit. Take the sentence (6) for example. In the sentence, the writer uses the item or to coordinate the three clauses to form a whole part, and then use but to introduce another kind of result that contrasts with what was said before.
　　Fourthly, I would like to have a look at the sentences (7). When we first read this sentence, we could only find the subject that but no predicate. Actually, in order to avoid repetition of the same lengthy wording, the writer used that in the beginning of this sentence to substitute for the clause in the preceding one they will help you to live more fully.
　　Finally, it is easy for us to realize the lexical cohesion in this passage as well. The choice of words clearly implies the central meaning: reading for pleasure. We could find there are a lot of words relating to reading used in the text. Almost all sentences have the expression about reading. Here are words appearing in it except for those referent items:
　　 reading many books to read reading get through them such books reading the books I shall mention
　　Besides, the writer also used different expressions to indicate the meaning of pleasure: enjoyable, enjoyment, alacrity, to live more fully, enjoy. As Halliday suggested, lexical cohesion may be maintained over long passage by the presence of key words, words having special significance for the meaning of the particular text [Halliday: 2006]. The use of lexical cohesion helps to hold the main idea in this text.
　　Ⅳ Conclusion
　　In order to create a text, we have to tie words and clauses together; we have to construct the text along the same systematic line. Cohesive devices such as reference, ellipsis, conjunction and lexical cohesion make it possible for us to gain a coherent text. It is useful for us to analyze the process of cohesion. It helps us a lot with our reading; and it facilitates our writing as well. With the knowledge of cohesion, it would be unlikely for us to deviate from the topic and to produce nonsense passages. As Thompson said, coherence is in the mind of the writer and reader: it is a mental phenomenon and can not be identified or quantified in the same way as cohesion [Thompson: 2005]. Cohesion is the main means used to express coherence in any text. Therefore, it is crucial for us to take advantage of cohesive devices in creating a text.
　　
　　References：
　　[1]Halliday.An Introduction to Functional Grammar[M].Foreign Language Teaching and Research Press，2006.
　　[2]Halliday and Hasan. Cohesion in English[M].London：Longman，1976.
　　[3]Thompson.IntroducingFunctionalGrammar[M].Foreign Language Teaching and Research Press，2005.
　　[4]Van Dijk. Tex and Context: Explorations in the Semantics and Pragmatics of Discourse[M].London：Longman，1977.
　　[5]张德禄.论衔接[J].外国语，2001，（2）.