| The Theme-Rheme Theory and Thematic Progression Theory have been applied a lot in Discourse Analysis in recent years. The notion of Theme was first put forward by Henri Weil and then developed by many other scholars. Among them, Halliday's Theme-Rheme Theory is applied most frequently. The Thematic Progression Theory is proposed by Danes (1974) and he put forward three thematic progression patterns., Many other scholars made further studies based on his study and the objects of the studies have covered nearly all genres of discourses. However, the contrastive studies of addresses, especially the official addresses are still scarce.Therefore, this thesis makes a contrastive study of choice of theme and choice of thematic progression pattern between American and Chinese leaders'addresses based on the Halliday's Theme-Rheme theory and Dane's and Huang Yan's Thematic Progression patterns, which aims at exploring the similarities and differences in the choices of theme,and the choices of thematic progression patterns and finding out the features of the discourses. Five TP patterns are adopted in this thesis: Constant Theme Pattern, Constant Rheme Pattern, The Simple Linear Pattern, The Alternative Pattern and Irregular Pattern.Sixteen American and Chinese leaders'addresses selected randomly on the Internet are adopted as the discourses of the study and they will be analyzed in qualitative and quantitative way. The major findings are as follows:First, there exist marked themes, textual themes and clausal themes in both types, the interpersonal theme is hardly existent. Besides, the Constant Theme Pattern and the Constant Rheme Pattern occur more frequently than the other patterns in the two types of texts.Second, unmarked themes are used more in Chinese texts than in English texts. The marked themes, however, occur more in English texts. For the textual themes, the number in English far exceeds to the number in Chinese texts. So do the clausal themes.Third, in Chinese texts, the Constant Rheme Pattern plays a dominant role while in English, the Constant Theme Pattern plays first.Fourth, the underlying factors that cause the similarities and differences in the choice of theme and choice of thematic progression patterns are communicative purpose, linguistic features and different ways of thinking.Finally, the flow of the old and new message has great dealings with TP patterns, especially the Constant Theme Pattern and Constant Rheme Pattern. |