英语论文网

udents’ comprehensive ability accurately and effectively in all aspects, including the ability in vocabulary, grammar and pragmatics. Therefore, this study takes CLEC as the research object, with an aim to analyze the characteristic of TSOT in complex sentence with object clause. Tense is taken as a grammatical category of the verb. Verb, along with noun, adverbial, adjective and other speeches, is the core speech in English .Meanwhile, It transforms greatly in tense and voice so that Chinese ESL learners usually make mistakes. According to statistics in CLEC, a total of 59,718.9 times speech errors were tagged, which the marked verb errors reached by 9002.6 times. The verb error has the highest frequency among the tagged errors of different parts of speech, which takes up 15.07% of the total errors, nearly two times of the noun error rate (8.39%).It is shown clearly in figure 1.1.

.........

Chapter Two Literature Review

2.1 Grammatical Perspective
First of all, a large number of concerned studies have been done by grammarians and linguists at home and abroad from the grammatical perspective. Quirk (1985) proposes the concept of “back-shift “for the first time in the book of A Comprehensive Grammar of the English Language and defines it as the variation of verb morphology which is essential when the reference time of the original utterance or mental activity isn’t applied for the time that the utterance or mental activity is reported. The relationship of verb forms between the matrix clause and the subordinate clauses is considered as “the sequence of tenses”. He also points out that if the reference time is still valid at the reported utterance time. Then, back-shift is optional, that is to say, whether it needs to move depends on the speaker's intention and their reference points of the reported utterance. Qin Yuxiang (2005) points out that the back-shift of the simple present tense is for the purpose of stating past, but without back-shift is to confirm present. For example: From the angle of meaning and grammar, both sentence (10) and sentence (11) are right.But they have certain difference in meaning. The tense of indirect speech is the simple past tense in sentence (10), whose reference point is the tense in reported verb and constructs a simultaneous relation between them. Joos(1964),Palmer(1974),Yi Zhongliang(1999) and Qin Yuxiang (2003) all claim that the simple past tense represents remoteness. It belongs to time distance in the example (10), which is decided by the distance between reported verbs and present speaking time .In this way, it shows that the speaker just quotes the speech without making any comment on its authenticity. The tense of indirect speech is the simple present tense in sentence (11), whose reference point is present speaking time and constructs simultaneous relation. Qin Yuxiang (2004) argues that the simple present tense represents a certain kind of connection. It is a kind of present-connected relation in time, which is showed by the authenticity between reported verb and present speaking time. In this way, it manifests that the speaker confirms the authenticity of the speech in the process of quotation.
...........

2.2 Discourse-Pr