Abstract Previous studies of Chinese modal verbs in the traditional framework (e.g. Lu 2004 ; Peng 2007 ; Tang 2000 ; Tiee 1985 ; Tsang 1981 ; Xie 2002 ; Xu 2007 ) have mainly focused on the description of semantic and syntactic features of modals that occur in the middle of the clause and attached little significance to the functions that modal verbs serve when they appear at different positions in the clause. Similarly, in a systemic functional framework, modal verbs in the middle of the clause receive the most attention. Their interpersonal functions are thoroughly explored; however, their textual functions are seldom discussed as they are believed to mainly appear in the middle of the clause buried in the Rheme rather than at the beginning or at the end of the clause. This paper examines the functions that modal verbs serve when they occur in different places in the clause from the perspective of systemic functional grammar. It argues that modal verbs are functionally motivated and the position of the modal verbs in the clause expresses particular meanings. When situated medially in the clause, modal verbs function as the Modality in the interpersonal structure of the clause, and as part of the Rheme in the thematic structure of the clause, marking the transition between Theme and Rheme. When occurring at the beginning or in the middle of the clause before a nominal group, some modal verbs of obligation serve as focus markers and identify the subsequent nominal group as the marked information focus of the clause. In the thematic structure of the clause, clause-initial modal verbs of obligation and probability function as interpersonal Themes to foreground the speaker’s modal assessment. Finally, when placed at the end of the clause, modal verbs serve either as the Predicator or Modality in the interpersonal structure of the clause and as the unmarked information focus of the clause.

中文翻译：

---

汉语从句中情态动词的系统功能研究

摘要 以往在传统框架下对汉语情态动词的研究（如卢 2004 ; 彭 2007 ; 唐 2000 ; Tiee 1985 ; 曾 1981 ; 谢 2002 ; 徐 2007 ）情态动词出现在从句的不同位置时所起的作用无关紧要。同样，在系统功能框架中，子句中间的情态动词最受关注。他们的人际功能得到了彻底的探索；然而，它们的文本功能很少被讨论，因为它们被认为主要出现在埋藏在韵律中的从句中间，而不是在从句的开头或结尾。本文从系统功能语法的角度考察情态动词出现在从句中不同位置时的功能。它认为情态动词是功能性动机的，情态动词在从句中的位置表达了特定的含义。当情态动词位于从句的中间时，它在从句的人际结构中充当情态，在从句的主位结构中作为韵母的一部分，标志着主位和韵母之间的过渡。当出现在名词性组之前的从句的开头或中间时，一些义务情态动词作为焦点标记，并将其后的名词性组识别为从句的标记信息焦点。在从句的主位结构中，义务和概率的从句开头的情态动词作为人际主题来突出说话者的情态评估。最后，当置于从句末尾时，情态动词在从句的人际结构中充当谓语或情态，并作为从句的未标记信息焦点。