中文摘要：

介词和名词组成介词结构，基本功能是引介，连词的基本功能是连接。对连词和介词所作的区分主要考虑的是语义关系。介词和连词的区别并不总是那样清晰，学界纷纷提出“关系词”、“连介词”等概念，甚至有人主张完全合并介词和连词。古汉语中关系词“虽”在发展过程中经历了一个语法化过程，从“连介词”完全变成了连词。

英文摘要：

A preposition and a noun compose a preposition structure. The basic function of a preposition is to introduce, while that of a conjunction is to connect. Analyzing the semantic relation is the common way to distinguish between the two kinds of words. In fact, the difference between a preposition and a conjunction is not always so clear, so scholars have put forward concepts like the “relation word” and the “preposition-con-junction”, even some people advocate that the difference between prepositions and conjunctions should be for-gotten. In ancient Chinese, the word “sui” has gone through a process of grammarticalization during its devel-opment, in which it turned from a preposition-conjunction completely into a conjunction.