Language is an important semiotic system. The nature of interaction is the communication and exchanges of information. Speech act refers to the fact that people use language to do something. Speech act theory originated with the British philosopher John Austin. Researches on speech act start with the study on the functions of language in daily life. Until now so many scholars conduct researches on the daily language based on speech act theory. With the development of mass media, people tend to use Internet more and more frequently. As a result, the Internet becomes an important part in people’s daily life. People use the Internet to learn, to socialize and to have fun. Media discourse is a complex system which consists of diverse categories. Nowadays, WeChat as a kind of mass media is popular. This article will conduct a research on the titles of articles in WeChat based on the speech act theory. Meanwhile, some feasible suggestions on how to write a good title are put forward.

It is assumed that thematic progression (TP) patterns are correlated with genres including narration, exposition, description and argumentation. In order to figure out the distributions of TP patterns in narration and exposition, the present study conducts a comparative study. It adopts four TP patterns: continuous pattern, TP with continuous Theme, TP with continuous Rheme and alternative pattern. Two texts are chosen randomly from New Horizon English Course (Reading and Writing) [1], a textbook for non-English majors in China, as representatives of narrative and expository writings. This paper can be divided into five parts. First, this paper presents the background of this study. Then it introduces the theoretical framework involving thematic structure and different thematic progression patterns. As the main body, the third part focuses on the quantitative comparative analysis of distributions of TP patterns in the two genres. The fourth part is results and discussion and the final part is conclusion. The result shows that though both genres incline to utilize TP with continuous Theme and continuous pattern, narration prefers TP with continuous Rheme while exposition tends to utilize more alternative pattern. This paper testifies the statement that there exist differences between distributions of TP pattern in narrative and expository writing. It also attempts to provide enlightenments for guiding the teachers to help improve students’ reading and writing abilities.