1、条件状语从句条件状语从句在复合句中表示主句动作发生条件的状语从句。so/as long asifunless二、结构与时态if如果如果是否是否:条件状语从句条件状语从句:宾语从句宾语从句=whether=whether（时态根据语境而定）（时态根据语境而定）二、结构与时态if引导的条件状语从句主将从现主将从现主情从现主情从现主祈从现主祈从现1.主句主句是一般将来时，是一般将来时，if从句用从句用一般现在时。一般现在时。主将从现If it rains,I will stay at home.If 从句主句If 从句在主句前时，_ 逗号隔开。If 从句在主句后，_逗号。用用不用不用2.主句主句 m
2、ust,may,can 等情态动词等情态动词，从句从句也要用一般现在时。也要用一般现在时。主情从现You must stop if the traffic is red.If 从句主句3.主句主句是祈使句，是祈使句，从要从要用一般现在时。用一般现在时。主祈从现Please call me if he comes next Sunday.If 从句主句1.If you _ to the party,youll have a great time A.will go B.went C.go D.going 2.If youre more careful,you _ much better.A.do
3、 B.will do C.are doing D.did3.I _ her the answer if she _me.A.can tell,will ask B.will tell,will ask C.would tell,ask D.will tell,asks 课堂练习课堂练习CBD4.Put up your hands if you _(have)any questions.5.If it _(be)cold tomorrow,I will wear my sweater.6.He can go home if he _(finish)his homework.haveisfinis
4、hesIf If 总结总结if如果如果主将从现主将从现主情从现主情从现主祈从现主祈从现是否是否Unless 如果不，除非 =if notUnless you go at once you will be late.如果你不马上走，就会迟到的。as/so long as:只要You will pass the examas long asyou keep on studying hard.只要你继续努力学习，你就会通过考试。只要你继续努力学习，你就会通过考试。课堂练习课堂练习1.She says that she will have to close the shop _ business improves.A if B or C unless D because2.If she _ tomorrow，Ill call you.A.come B.comes C.will come D.came CBThank you
