Abstract
矣 yi is a sentence-final particle of declarative sentences in pre-Qin Chinese; its grammatical functions, however, are still a matter of debate. Traditional grammarians tend to treat it as a marker of mood, while, on the other hand, Pulleyblank (1994) insists that it is simply a marker of perfect aspect. In this paper, the author suggests that yi is possessed of both functions, resulting from semantic extensions in which the mechanisms of ＂metaphor of semantic structure＂ proposed by Sweetser (1990) and ＂subjectification＂ proposed by Traugott (1989) are involved. Lyons (1995) claims that tense, aspect, mood, and modality share the property of ＂subjectivity of utterance＂; yi in pre-Qin Chinese supports this claim.