1. or 用在选择疑问句中，意为“或者，还是”。例如：
Is she a worker or a teacher?
她是工人还是教师?
Did you do your homework or play games last night?
你昨晚做作业还是玩游戏了?
Are they listening to music or reading English?
他们是在听音乐还是在读英语?
2. 并列结构中，and 用于肯定句，or通常用于否定句表示“和，与”之意。
There are some teachers and students on the playground.
