1、条件状语从句引导条件状语从句的从属连词（短语）引导条件状语从句的从属连词（短语）1、unless 如果不，除非unless引导的从句中只能用肯定形式，unless引导的肯定条件状语从句可以转换成if引导的否定条件状语从句，即if not。Unless we try our best,we wont succeed.=If we dont try our best,we wont succeed.如果我们不尽力，我们就不会成功。2、if如果 所引导的从句常用一般现在时，主句用一般将来时。If he practices it,his handwriting will certainly impro
2、ve.如果他练习，他的书法一定会进步。3、as long as只要 所引导的从句常用一般现在时，主句用一般将来时。You wont have to worry about the final exam,as long as you work hard.只要你认真学习，你就不必担心期末考试。注意：当if、unless、as long as引导条件状语从句时，主句和从句的时态采取“主将从现主将从现”原则。条件句用于陈述语气，表示假设的情况可能发生，其中 if 是“如果”的意思。条件从句主句If一般现在时主语will/may/might+动词原形If he comes,he will take us
3、 to the zoo.1.如果主句是一般将来时，从句则用一般现在时。如果主句是一般将来时，从句则用一般现在时。If it rains（从句），（从句），I will stay at home.Ill go with you if you dont want to go alone（从句）（从句）.2.如果主句含有如果主句含有must,may,can 等情态动词，从句也要用等情态动词，从句也要用一般现在时。一般现在时。If you drive too fast,you may have an accident.You must stop if the traffic is red.3.如果主句
4、是祈使句，从句同样要用一般现在时。如果主句是祈使句，从句同样要用一般现在时。Dont go and play football if you dont finish your homework.Please call me if he comes next Sunday.4.表示假设，表示将会发生和可能发生的事，表示假设，表示将会发生和可能发生的事，或进行提醒警告。或进行提醒警告。If+句子（一般现在时），句子（一般现在时），+主句（主语主句（主语will/may/can)+动词）动词）If you finish your homework,you can go out and play.If
5、 I have enough money next year,I will go to travel.下列从句中的下列从句中的will不是将来时助动词，而是情态动词。不是将来时助动词，而是情态动词。翻译为翻译为“愿意愿意”。If you will excuse me,I really must go to bed.如果你能原谅我的话，我真的要睡觉了。如果你能原谅我的话，我真的要睡觉了。If you will wait a minute,Ill go and tell my mother that you are here.如果你愿意等一会的话，我去告诉我妈妈你来了。如果你愿意等一会的话，我去告
6、诉我妈妈你来了。完成句子1.如果你请求他，他会帮你的。If you _him,he _ _you2.如果她早点儿起床，就有时间在家里吃早餐。If she_ _a little earlier,shell have time to eat breakfast at home.3.如果你参加聚会，你将会过得很开心。If you_ the party,you_ _ a great time.4.如果明天下雨，我们将不去野餐。If it _tomorrow,we _ _ for a picnic.5.如果你经常听英文歌，你将会喜欢英语。If you often _ _English songs,you
7、_ _ English.askwill helpgets upjoinwill haverainswill golisten to will like 一般情况下，一般情况下，unless相当于相当于ifnot，可以互，可以互换。注意当主句是一般将来时态时，从句常换。注意当主句是一般将来时态时，从句常用一般现在时代替将来时。例如：用一般现在时代替将来时。例如：I wont let you in unless you show me your pass=I wont let you in if you dont show me your pass.如果你不出示通行证，如果你不出示通行证，我就不让
8、你进来。我就不让你进来。If it doesnt rain,I will/may go to the zoo.Unless it rains,I will/may go to the zoo.unless=if not误误:Dont come in unless you will be invited to.正正:Dont come in unless youre invited to.误误:Unless he will come,we wont be able to go.正正:Unless he comes,we wont be able to go.I _(go)with you if
9、you_ (not want)to go alone.2.Unless you _(work)hard at math,you _(not be)better at it.dont wantwont beworkwill go as/so long as 表示条件，意思是“只要”。As long as you tell the truth，Ill try to help you.只要你告诉我实情，我会尽力帮助你。You may take this book away so long as you return it on time.只要你按时归还，就可以把这本书拿走。I dont care s
10、o/as long as she lets me be with her son.只要她让我和她儿子在一起，我不在乎。You can take my car as/so long as you drive carefully.你可以用我的汽车，只要你小心点儿开。You may use my dictionary as/so long as you dont keep it too long.只要使用时间不太长，你可以用我的词典。“祈使句+and(or)+陈述句”在意思上相当于一个带有条件状语从句的复合句。Hurry up,or youll be late.If you dont hurry u
11、p,youll be late.将下面句子改成含有if的复合句Study hard and you will pass the exam.If you study hard,you will pass the exam.Youd better travel around Nanjing with a local tour guide _ you want to learn more about its culture.A.unless B.until C.although D.if 2.If there _ no buying and selling of animals,there _ no
12、 killing in the future.A.is;will be B.will be;will be C.is;is D.will be;is 3.There are fewer and fewer tigers in India.The situation will continue _ humans stop hunting them for their fur and bones.A.if B.unless C.because D.since4.-Can Mr.King spare some time for the charity show?-If he _,he will tr
13、y his best to make it.A.Will be invited B.is invited C.invites D.invited5.-This is between you and me.-I promise.I wont tell others _ you say I can.A.unless B.or C.since D.and6.Im waiting for my friend._,Ill go shopping alone.A.If she comes B.If she wont come C.If she doesnt come D.If she will come
