精选优质文档-倾情为你奉上If 用法汇总1、主将从现 （主句为一般将来时,从句为一般现在时）；eg:If it rains(从句) ,I will stay at home（主句）.=I will stay at home if it rains.2、主句含有情态动词 （must、may、can etc.）从句为一般现在时；eg:If you drive too fast ,you may have an accident.=You may have an accident if you drive too fast3、主句为祈使句,从句要用一般现在时态；eg:Dont play computer games if you dont finish your homework.4、 是否=whetherAsk if he is at home. I wonder if she is ill.5、 虚拟语气 eg:If I were a bird ,I would fly in the sky.（事实我不可能是
