连词的定义
连词是一种虚词，不能担任一个句子成分。连词在句中主要起连接词与词、短语与短语及句子和句子的作用。它主要是包括并列连词和从属连词。
并列连词的用法：
1、 并列连词and和or：
①and 和or 是用得最多的并列连词，可以连接：
a. 两个并列的动词： We were singing and dancing all evening. 整个晚上我们都在唱歌跳舞。
b. 名词、形容词等：This apple is big and red. Would you like fish or beef?
c. 两个并列的分句(句子)：I said it and I meant it. 我说话算数。
②and 可连接两个分句，表示递进关系。 Give him an inch and he will take a mile. 他会得寸进尺。
③or可连接分句，表示"否则"：
Don't drive so fast or you'll have an accident. 别开这么快，不然你会出车祸。
2、 表示意思转折的连词：but, yet:
①but和yet的用法：
The weather will be sunny but cold. 天气会晴朗但很冷。
It is strange, yet true. 这很奇怪，却是真的。
②however, still 等为副词，但可起连接作用，表示意思的转折---"但是"或"然而"。
a. however: His first response was to say no. Later, however, he changed his mind.
他的第一反应是不行，但后来他改变了主意。
b. still: It's raining; still I'd like to go. 天在下雨，但我还是要去。
③词组all the same: She is naughty, all the same we have to laugh at her jokes.
她很调皮，但对她的恶作剧我们还是要发笑。
3、表示因果的连词：
① for可以表示"因为"，但引导的不是从句，而是并列分句，对前面情况加以解释，常用逗号把它和前面的分句分开，这在书面语中比较多见。
The days were short, for it was now December. 白天很短，因为现在已经是十二月。
She must have gone out early, for she had not come for breakfast.
她肯定一早出去了，因为她没来吃早饭。
② so 表示结果，可译为"因此"、"所以"。
Our cases were heavy, so we took a taxi. 我们的箱子很重，因此我们坐了出租车
③ therefore 为副词，也表示同样的意思---"因此"，可放句前：
He had gone; she therefore gave the money to me.他走了，于是她把钱给了我。
4、both... and 的用法
A man should have both courage and perseverance.一个人既要有勇气又要有毅力。
5、就近原则：
1)neither…nor… Neither Lucy nor Lily is a League member.
2)not only…but also… Not only you but also he likes football.
3)either…or… Either Jim or Peter is right.
4)not…but… Not Jim but Peter broke the cup.
6、as well as的用法:
I have read one of his novels as well as a few of his plays. 我读过他的一本小说和几个剧本。
