本文探討漢語「行」，特別是討論現代漢語「行」的情態用法之演變。本文先將現代漢語「行」的句法分布作一介紹與討論。現代漢語「行」主要出現有句首單用、謂語、A-不-A、疑問 /詰問及副詞搭配用法。接著，本文再藉由上古漢語、中古漢語，以及近代漢語的語料，理解現代漢語「行」情態用法的出現。在上古漢語及中古漢語，「行」主要還是動詞用法。「行」在近代漢語，同時使用動詞用法及情態用法。除了華語以外，本文也藉由四個南方方言 (客語、粵語、台灣閩南語、海南閩語 )的語料，論證「行」的情態用法可能來自「得」。南方方言使用「得」來表達現代漢語「行 f」的情態用法。其中，海南閩語之「得」更與「行」有非常接近的句法分布。此外，「得」與「行」在近代漢語開始大量同現 (co-occur)，也支持本文的推論，即是「行」經由句法的聚合關係產生了語意改變，即為現代漢語「行」的情態用法。

The present study explores xing in Chinese, especially focusing on the derivation of modal usage of xing. This paper introduces the syntactic distribution of xing in Modern Chinese. Through data in Old Chinese, Middle Chinese and Early Chinese, this paper finds that xing emerges to function as a modal since Early Chinese. This paper also employs data from four Southern Chinese dialects (Hakka, Cantonese, Taiwan Southern Min, Hainan Min) to argues that the modal meaning of xing may be affected by de ‘acquire,’which expresses modality in archaic Chinese. Unlike Modern Chinese, the four dialects remain to colloquially use de as a modal word, rather than xing. De in Hainan Min has very similar distribution with xing in modern Chinese. In addition, de and xing start to frequently co-occur in Early Chinese. The archaic data also support the argument of the paper that xing undergoes a semantic change via syntagmatic relationship from an activity verb to a modal.