As English continues to change in both spoken and written communication, the use of modal expressions has also shifted. Core modal auxiliaries such as must and shall appear to be less dominant, while semi-modal constructions such as have to have become increasingly common. This study investigates the diachronic change and functional relationship among must, shall, and have to in American English. It aims to examine whether must and shall decline over time, whether have to rises, and whether have to can partially replace must in expressing obligation or necessity. Using COHA and COCA as the main data sources, this study combines frequency analysis, register comparison, Pearson correlation, and semantic coding of concordance lines. The results show that must and shall decline over time, while have to increases significantly, especially in spoken English. The study concludes that have to represents a partial functional replacement of deontic must and reflects broader processes of colloquialization and semi-modalization.

The deep penetration of digital media and the traffic-driven communication paradigm have driven China’s traditional drama industry to break away from its inherent theater-centric and audience-stratified patterns, bringing about a structural restructuring of the industrial ecology. Adopting a dual perspective of media convergence and cultural industry studies, this paper systematically examines the ecological transformation of the drama industry in the traffic era, the breakout mechanisms of niche dramas, and emerging commercial models. It also addresses the minor impacts of youth traffic culture, identifies contradictions in industrial transformation, and explores sustainable development strategies suited to the digital context. The prevalence of short-video platforms, social media, and live-streaming has removed temporal and spatial barriers to drama dissemination, reshaping the production logic, audience structure, and commercial models of stage art. It has also created a new pathway for niche original and experimental dramas to achieve mainstream visibility. Traffic empowerment has decentralized artistic communication, expanded the public reach of drama, and enabled diversified commercial monetization. Meanwhile, traffic-driven communication and a light community support culture are emerging among youth groups, injecting vitality into the drama market; however, they have also led to superficial aesthetics and inflated popularity. The fast-paced nature of traffic dissemination, profit-driven capital orientation, and formulaic creation logic inherently conflict with drama’s core values—narrative depth, critical reflection, and humanistic connotation. This tension has resulted in challenges such as superficial content, homogenized production, inefficient traffic conversion, and an immature industrial system.

With the deep popularization of social media, the social modes and self-expression paths of young people are constantly changing, and WeChat Status has gradually become a new daily expression space for young groups. Taking Foucault's "technologies of self" theory as the analytical framework, this study adopts the questionnaire survey method to conduct an empirical study on the WeChat Status usage behavior of young people aged 15-29, with a total of 173 valid questionnaires collected. It aims to explore the practices of self-expression, self-regulation and identity construction of young people in the semi-private digital social field. The study found that WeChat Status enables young people to express their emotions in a more relaxed and immediate way. Compared with maintaining a social image of "being seen", more and more young people are beginning to care more about "expressing themselves truthfully".