所谓平行结构就指的是内容相似，结构相同，无先后顺序，无因果关系的并列句。从总体上来说，平行结构可以分为以下的几种类型：
一、连词连接两个对等的词和对等的结构
并列连词and, but, as well as, or, or else, both … and, neither … nor, either … or, not only … but (also), rather than,as…as等以及从属连词than可连接两个对等的词和对等的结构。
1.所连接的谓语形式必须一致
例1：He went downtown, bought some books and visited his daughter.
例2：Gunpowder was discovered in the twelfth century, but not used in warfare until two hundred years later.
2.所连接的词或短语形式必须一致
例1：Your semester grade is based not only on how well you do on each test, but also on how you participate in class.
例2：We often go to the countryside as well as to factories.
例3：I would much rather go to the countryside than stay here.
3.连接的非谓语动词的形式必须一致
例1：Some find swimming more enjoyable than sitting at home reading.
例2：He was engaged in writing a letter rather than reading the newspaper.
4.所连接的句子结构必须一致
例1：She is pleased with what you have given and all that you have told him.
例2：The purpose of the research had a more different meaning for them than it did for us.
二、某些特定的固定结构。例如：
(1)有些词后要用平行结构。例如：
prefer sth to sth
prefer doing sth to doing sth
prefer to do sth rather than do sth
1) I prefer rice to noodles.
2)I prefer watching TV to listening to music.
3) He preferred to die rather than surrender.
(2)有些结构中要用平行结构。例如：
would / had rather / sooner do something than do something, would / had as soon do something as do something (宁可……也不……)
1) Liu Hulan said she had rather die than give up.
2) I would as soon stay at home as go.