.common,usual和ordinary的区别
（1）common意为"普通的","平常的",指常见的,常常发生的,不足为奇的.如：
The birds are very common here.这些鸟在这儿很常见.
The common man in every country is anxious for world peace.
每个国家的老百姓都渴望世界和平.
Snow is common in cold countries.在寒冷的国家雪是常见的.
（2）usual意为"通常的","习惯性的",可用于一切频繁发生的事情.如：
Tea is considered to be the usual drink in Britain.在英国,茶被视为一种习惯性的饮料.
He arrived later than usual.他到得比平常晚一些.
Are you coming home at the usual time?你准备按往常的时间回家吗?
Yes,I shall leave the office at the same time as usual.
是的,我将和平常一样准时离开办公室.
My usual chair had been moved from its usual place.我平常用的椅子已从老地方移开了.
（3）ordinary意为"通常的","普通的",有"日常的","随时都可以碰到的"含意,与common意思相近.如：
An ordinary workday is eight hours.一个工作日通常是八个小时.
It was a very ordinary day today.今天是很平常的一天.
He is a little man with ordinary looking.他是个个子矮小,相貌普通的人.
Tom Sawyer was an ordinary American boy who kept getting into trouble.
汤姆·索耶是个常常惹事生非的普普通通的美国男孩.