不可否认，被动句是一种非常重要的语法结构，引起了语言学家的极大兴趣。传统的英语语法教学只注重不同语法形式的句型转换。换言之，传统英语语法在句法层面上研究被动句，随着现代语言学的迅速发展，许多学者从不同的角度研究句法问题。以往对被动语态的研究多是汉英被动语态的比较。韩礼德提出了语言的三种元功能，即概念功能、人际功能和语篇功能，这对语法功能的研究具有指导意义。在大多数情况下，文本功能被用来解释话语分析，而本文研究的是语法结构——被动句的文本功能的三个子范畴，即主位结构、信息结构和衔接。被动句作为一种句法现象，在科技语篇中是非常明显的。也就是说，它是科学技术风格的显著特征之一。
Chapter 1 Introduction
1.1 Background of the Study
There is no escaping that passive sentence is a very important grammaticalstructure, which arouses many linguists’ interests. Traditional English grammarteaching only lays emphasis on the sentence patterns transformation of differentgrammatical forms. In other words, traditional English grammar studies passivesentences on the level of syntax basically.With the rapid development of modern linguistics, many scholars studysyntactic problems from different perspectives. The previous studies of passive voiceare mostly about the comparison of Chinese and English passive voice. Hallidayproposes three meta-functions of language, i.e. ideational function, interpersonalfunction and textual function, which are instructive to the study of the functions ofsyntax. In most cases, textual function is used for the explanation of discourseanalysis, while this thesis studies grammatical structure — passive sentence by virtueof the three subcategories of textual function, i.e. thematic structure, informationstructure and cohesion. Passive sentence, as a syntactic phenomenon, is extremely obvious in Scienceand Technology discourse. That is to say, it is one of the prominent characteristics ofScience and Technology style. In the light of being concise and objective, sometimesEST tends to use passive sentences rather than corresponding active ones. Therefore,EST is taken as data in the thesis.
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1.2 Objective and Significance of the Study
The main purpose of the thesis is to explore the textual functions of passivesentences in terms of thematic structure and information structure as well as analyzepassive sentences based on the context of the use of cohesion. The study will offer anew perspective for the understanding of passive structure, which will eliminate theindifference to passive sentences of traditional view.In addition, as passive sentences are widely used in EST, this study willfacilitate people’s understanding of EST. On one hand, to master more knowledge onpassive sentences will do good to the readers, who can obtain a better understandingof the English for Science and Technology materials. On the other hand, writers willbenefit from the study in that adequate knowledge of this area will be beneficial to thewriters’ information organization.What’s more, it is hoped that the functional analysis of passive sentences willenable people to understand that it is important to learn language with functions,which will contribute to the acquisition and teaching of language so as to improve thelearners’ communicative competence.
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Chapter 2 Literature Review
2.1 Passive Sentence
In this section, the definition and classification of passive sentence areillustrated as follows.Passive sentence is a common syntactic phenomenon in English. Leech et al(1975) offers the term “passive” is used to describe: (A) the type of verb phrase whichcontains the construction be + past principle; (B) the type of clause in which a passiveverb phrase occurs. Zhang Zhenbang (2003) suggests that passive sentences are thesentences or clauses that take passive phrases as predicates.In English Grammar books, “passive voice” tends to be seen more frequentlythan “passive sentence”. Bao Bing (1990) proposes that English voice is divided intoactive and passive voice. Active voice shows the subject is the “doer” of the actionexpressed by the predicate verb. Passive voice expresses that the subject is the“sufferer”. Halliday (1989) puts forward that voice is a grammatical category which isnot only related to the verbs denoting process, but also associated with other elementsof the clause in traditional grammar. In functional grammar, if tra
