1 and. but. or ，并列连词，放在第二句首。
2 并列连词在连接两个分句时，其位置固定在所引导的分句的句首。如:
He likes volleyball, but he can't play it well.
3两个并列连词不可以连用。
4并列连词不可以与从属连词连用。如(因为/所以，不同时使用)。
以and 为代表的，表示意义引申的并列连词用法:
and
(1)表增补，补充(递进)。
(2) and连接谓语动词时，表动作的连续。如
Tom saw me and come and sat at the same table.
(3)肯定条件＝条件句的变体。
a: 祈使句＋and ＋will/shall陈述句。
b :祈使句＝If肯定的条件句。
如 Work hard and you'll pass the exam.→ Work hard ＝If you work hard.
(4)对比表“而”。
Mary is interested in music and Jim is fond of sports.(表对比)
(5)表结果“所以/因此”。
I had just lost 50 pounds and I felt
very upset.
but
1表意义转折。
I left my money in the room,but it is missinging now.
2 表对比或对照(与否定词not,little never,hardly 连用)。如
not ~ but~不是~而是。
The umbrella is not mine but hers.这把伞不是我的而是她的。
3 对比项不一定是平衡。
or
1表选择。
2 表同位关系或换个说法。“或者/也就是”。如
Soccer or football is popular all over the world.
3大约或不确定的情况。“或者”。如
Mr Li or Mr Liu called you yesterday.
4表否定条件。or＝or else.“要不然的话/否则的话” 有二种情况:
(1)祈使句＋or＋陈述句( will/shall＋动词),祈使句是if引导的否定句。
如Hurry up or you'll be late for the last train. ＝ If you don't hurry up , you'll be late for the last train.
(2)祈使句＋and ＋陈述句( will/shall＋动词)。祈使句是if引导的肯定句。
5 否定句中用or代替and.
