1.引起条件状语从句的连词：
l) if 如果，假如：
lt doesn't matter if you can't find her.
如果你找不到她也没有关系。
If you do it, so can I.
你要是能办到，我也能办到。
2) even if 即使：
They'll stand by you even if you don't succeed.
即使你不成功，他们也会支持你。
We wouldn't lose heart even if we should fail ten times .
我们就是失败十次也不灰心。
3) unless 除非(……否则)，如果不：
Don't Come unles I telephone.
我不打电话你就别来。
You won't catch the bus unless you run.
除非你跑，否则你就赶不上公共汽车了。
4) incase 如果，以防：
Incase I forget, please remind me about it.
如果我忘了，请你提醒我。
We'd better take our raincoats in case it should rain.
我们最好带上雨衣以防下雨。
5) provided (that)要是，只要：
I'll come provided (that) you let me know in good time.
你要是及时通知我，我是会来的。
They may swim provided an adult accompanies them.
只要有大人陪，他们可以去游泳。
6) suppose (supposing)假定，要是：
Suppose (Supposing) (that) he won't agree, what shall we do?
假定他不同意怎么办?
Supposing the Plane is late?
要是飞机晚点了呢(怎么办)?
7) as Iong as 只要：
I am happy as long as you are happy.
只要你高兴我就高兴。
As long as you understand, we shall say no more about it.
只要你理解，我们就不再说什么了。
8) on condition that 只要，条件是：
I'll come on condition that John is invited, too.
只要也邀请约翰，我就来。
You may borrow the book, on condition that you do not lend it to anyone else.
你可以借这本书，条件是你不把它借给别人。
