(1) 表示联合,意为“和”、“又”、“而且”:We were cold and hungry. 我们饥寒交迫。I woke up and got out of bed. 我醒了就起床了。He played the piano and she sang. 他弹钢琴,她唱歌。(2) 有时用于连接两个相同的词语,表示事物连续性:The train ran faster and faster. 火车开得越来越快。We waited for hours and hours. 我们一直等了好几个小时。我们一直等了好几个小时。The boys laughed and laughed. 这些孩子笑个不停。注:但有时连接两个相同名词表示不同的质量和种类:There are dictionaries and dictionaries. 词典很多,有好有坏。Don’t worry—there are rules and rules. 别担心规则与规则不一样。(3) 在口语中用在 come, go, run, stay, stop, try 等之后表示目的,大致相当于相当于不定式符号 to:Come and have tea with me. 过来跟我一起喝杯茶。We ought to stop and think. 我们应该停下来想一想。(4) 有时用在祈使句后,表示结果,意为“那么””:Work hard and you'll succeed. 努力干吧,你会成功的。Arrive late once more and you’re fired. 你再迟一次,你就会被开除。比较:If you work hard, you'll succeed. 如果你努力干,你会成功的。如果你努力干,你会成功的。(5) 有时表示对比(有类似but的意思):He is rich, and (yet) leads a modest life. 他很富有,但却过着朴素的生活。Robert is secretive and David is candid. 罗伯特深藏不露,而戴维则有啥说啥。(6) 用在 good, nice, fine 等之后,表示“很,“挺”:It's nice and cool under the tree. 这树下很凉快。The book is good and expensive. 这本书很贵。