条件状语从句表示主句的动作发生的条件、假想、推测或意愿。用连词 if, unless 和起连接作用的短语 except that; in case that; on condition that; provided/providing that; so/as long as; suppose/supposing that 引导。 用法: 1.从句表示的条件客观上是现实的,常用陈述语气,如: If the stamp is torn, it's no good for my collection.如果邮票是破的,那我收集起来就没有用了。 Suppose all the doors are locked, how will you get into the house? 假如所有的门都锁上了,你怎么会进到这所房子呢? 2.从句表示的条件同事实相违背或不可能实现,通常用虚拟语气。如: If I were captain of a ship, I would take you on a voyage round the world.如果我是一艘轮船的船长,我将带你航海环游世界。 注意事项: 1.用一般现在时表示将来时。 The meeting will be held out of doors unless it rains.除非下雨,大会将在户外举行 2.用选择完成时替代将来完成时。 If I have made a mistake, I will try to remedy it.如果我犯了错误,我将会努力改正 3.will用在真实条件状语从句中是情态动词,表示意愿或决心,而不是单纯表示将来。 I will tell you if you will come on Friday.如果你愿意星期五来,我将告诉你。 还有其他一些情况,你暂时用不到,以后自己多注意。