从形式上看，连词可以分为简单连词(Simple Conjunctions)，如：and, but，副词连词(Adverbial Conjunctions),如：then, besides, still；短语连词(Conjunction Phrases)，如：as yet, or rather, on the other hand; 和关联连词(Correlative Conjunctions),如：so... that..., either... or..., not only...but 或后面跟某种副词，如：and...as well, but...all the same.