连词的主要作用是连接。从连接的成分来看，有的是连接词或短语，有的连接分句；从连接的方式来看，有的表示并列关系，有的表示偏正关系。介词起转介作用，用在名词、代词和短语后，表示时间、处所、方式、条件和对象等。一般情况下，连词和介词并不难区分，但“和、同、跟、? The main function of conjunctions is to connect. From the point of view of the composition of the connection, some are connectives or phrases, and some are connected to clauses. From the perspective of connection, some indicate a side-by-side relationship while others indicate a partial relationship. The preposition plays the role of referral. It is used after nouns, pronouns and phrases to indicate time, place, way, condition and object. Under normal circumstances, conjunctions and prepositions is not difficult to distinguish, but "and, with, with?