本研究目的是在探討中文「在」歷時的演變之語法結構與用法。隨著時間的過去，中文「在」語境使用範圍已擴大；不再局限在主詞是人，中文「在」目前可以與不同種類動詞一起出現，語境使用的增加也出現抽象的用法。使用範圍的延伸擴大導致使用頻率的增加。中文「在」從具體處所語意演變成抽象進行式的語意，無處所語意的進行式用法已有減少的趨勢。研究顯示中文「在」原本就兼具有時間與處所的語意，此發現支持語法普遍化的現象。研究也顯示中文「在」的語意演變與結構息息相關而非本身具有時間的語意而已。

This paper investigates the diachronic change of the Progressive morpheme zai in Mandarin Chinese. The context of the Progressive zai is no longer restricted to use with only human subjects, there is now a wide range of uses with semantic verb types and it has led to increase of occurrences with the abstract ‘in’. This increase in the context of use gives rise to an increase in frequency of occurrence. In addition, as locative meaning of the morpheme zai develops into Progressive, the meaning becomes more general or abstract since it involves a gradual loss of its original meanings. That is, there is a decrease of Progressive zai co-occurring with locative expressions. Evidence shows that both temporal and locative senses exist from the beginning of gram, which supports generalization as a main mechanism of semantic change in the development of Progressive zai. Furthermore, the data indicate that aspectual meaning of grams can primarily come from the construction rather than relying on other lexical temporal expressions.