if引导的条件状语从句的分类及虚拟条件句：
1、if 引导的条件状语从句有两种语气，一种是真实语气，一种是虚拟语气。
2、if条件句中如有were，should，had，可以省去if，并使用倒装语序。
3、在语法中if条件状与从句中的谓语动词如果是be其过去形式一般用were。
拓展资料
if的用法
1、The whole room looks as if it has been lovingly put together over the years
整个房间看起来好像是经过了多年的精心布置。
2、He points two fingers at his head, as if he were holding a gun
他把两根手指指向他的头，仿佛他正举着一支枪。
3、My husband, for some unknown reason, suggested that I loved my birds more than him: as if I would
我丈夫，莫名其妙地，暗示我爱鸟甚于爱他：仿佛我真如此似的。
4、Living together didn't harm our friendship. If anything it strengthened it
在一起住并没有损害我们的友谊。要说真有什么的话，它反而巩固了我们的友谊。
5、I am surprised by the fuss she's making. It's not as if my personality has changed.
她的大惊小怪令我很吃惊。显然不是我的个性改变了。
6、If I were you, Mrs Gretchen, I just wouldn't worry about it
要是我是你，格蕾琴夫人，我一点都不会担心。
7、You'll feel a lot better about yourself if you work on solutions to your upsetting situations
如果你设法找到解决自己麻烦的办法，你自我感觉会好得多。
8、You can go if you want
你要是想走就可以走。
9、If you would like to send a donation to Cobuild, please enclose a cheque with your coupon
如果你想为Cobuild语料库捐款，请随订货单附上支票。
10、If you went into town, you'd notice all the pubs have loud jukeboxes
如果你进了城，你会注意到所有的酒吧都有音量很大的自动点唱机。