连 词
定义：连词是一种虚词， 它不能独立担任句子成分而只起连接词与
词，短语与短语以及句与句的作用。
分类：根据在句中所起的作用，连词主要可分为并列连词和从属连词两
类。
并列连词：连接具有并列关系的词、短语或句子的连词叫作并列连
词。
根据意义，它又可分为表示联合、转折、选择和因果等四
种关系的连词。
一、表示联合关系的并列连词
表示联合关系的并列连词有：and, both…and, neither…
nor, not only…but also, as well as(除……外……也……)
等。
eg: I am a teacher and he is a doctor.
He has both experience and knowledge.
Neither I nor he has seen the film.
He has experience as well as knowledge.
He has not only experience but also knowledge.
二、表示转折关系的并列连词
表示转折关系的并列连词有 but, while(然而), yet(可是),
however(然而，但是)，nevertheless(然而，不过)等。
eg: I am sorry, but I won’t be able to come tonight.
I am willing, yet unable. 我心有余而力不足。
He is short, while his younger brother is tall.
