并列连词常可连接两个句子短语或单词，大体上可分为下面几类：
1.表示意思转折的连词:
l) but 但是：
He tried hard but he was unsuccessful.
他做了很大努力，但没成功。
she 's American but she lives in England.
她是美国人，但她住在英国。
2) yet 但是：
she has her weaknesses, yet she is honest.
她有她的弱点，但她很诚实。
The car was old, yet it was in good condition.
这辆车很旧，但处于良好状态。
3) however 但是，可是：
He said that it was so, he was mistaken, however.
他说情况如此，但他错了。
Most people, however, praised silas.
但多数人都赞扬赛拉斯。
2.表示因果关系的连词：
l) for 因为：
You'd better put on your sweater, for it's rather cold outside.
你最好穿上毛衣，因为外边相当冷。
It must be snowing, for it is so bright outside.
一定在下雪，外边这样亮。
2) so 因此：
My sister is expecting me, so I must be off now.
姐姐在等我，因此我得走了。
It was already rather late, so we decided to go home.
天已经相当晚了，因此我们决定回家。
3) therefore 所以，为此：
You are in the right, therefore we should support you.
你是对的，所以我们应当支持你。
He broke the rules of the school, therefore he had to leave.
他犯了校规，为此不得不离校。
4) hence 所以，因而(多用于说理文中):
The word is an uncountable noun and isued in a general sence, hence it takes no artide.
这字是不可数名词，又用于一般意义，所以不加冠词。
