a. 表示转折关系的并列连词。这类连词主要有 but, yet 等。

　　例如：Someone borrowed my pen, but I don’t remember who.

　　有人借了我的钢笔，但我不记得是谁了。

　　b. 表示因果关系的并列连词。这类连词主要有 for, so 等。

　　例如：The child had a bad cough, so his mother took him to the doctor.

　　这孩子咳得很利害，所以他妈妈带他去看医生。

　　c. 表示并列关系的并列连词。这类连词主要有 and , or , either…or , neither…nor , not only…but (also) , both…and , as well as(不仅…而且…) 等。

　　例如：He didn’t go and she didn’t go either.

　　他没去，她也没去。

　　He speaks Chinese as well as his teacher.

　　他汉语说得和他老师一样好。

　　This is important to you as well as to me.

　　这对你和我都很重要。