“当”的演变过程
The Evolution of “Dang”

“当”从本义“当，田相值也”语法化为助动词、副词、介词、连词。在其语法化的过程中，词义引申、语法结构的重新分析、语义环境等因素都起到了重要的作用。本文主要考察其作为助动词、副词、介词、连词时的用法及其演变，尝试分析其语法化的进程及其机制。
“Dang” is grammatically transformed from its original meaning “Dang, Tianxiangzhi” into auxiliary verbs, adverbs, prepositions and conjunctions. In the process of its grammaticalization, factors such as lexical derivation, re-analysis of grammatical structure, and semantic context all play an important role. This paper focuses on its usage as auxiliary verbs, adverbs, prepositions and conjunctions and its evolution, and tries to analyze the process of its grammaticalization and its mechanism.