1、Unit 7 条件状语从句 if引导的条件状语从句1. 含义在复合句中作条件状语的从句称为条件状语从句。常见的if条件状语从句表示在某条件下，某事很可能发生，条件是可能存在的，主句中某种情况发生的概率也是很高的。if 作连词，意为“如果”，引导条件状语从句。If it doesnt rain tomorrow, I will go climbing with my friends.主句If引导的条件状语从句2. 位置if条件状语从句可置于句首，要用逗号与主句隔开，也可置于句尾。例如：If it rains tomorrow, we will not go to the zoo. 如果明天下雨的
2、话，我们就不会去动物园（1）主句+if条件句。 例如：The cat will scratch you if you pull her tail. 如果你拉猫的尾巴，它就会抓你。（2）If 条件句+逗号+主句。例如：If you fail in the exam, you will let him down. 如果你考试不及格，你会让他失望的。 3. 时态主句从句一般将来时（will+动词原形）一般现在时情态动词（may/can/should/must+动词原形）一般现在时祈使句（动词原形开头）一般现在时一般现在时一般现在时（1）if从句用一般现在时，主句用一般将来时（主将从现）例如：If h
3、e runs, hell get there in time. 如果他用跑的，他就会及时赶到那儿。（2）if从句用一般现在时，主句用may/can/should/must+动词原形（主情从现）例如：If it stops snowing, we can go out. 如果雪停了，我们就可以出去。If you want to lose weight, you must/should eat less bread. 如果你想减肥，你必须少吃面包。（3）if从句用一般现在时，主句用祈使句（主祈从现） 例如：Put on your coat if your are cold. 如果你冷的话，穿上外套
4、吧。If it rains tomorrow, please stay at home.如果明天下雨的话，请待在家里（4） if从句用一般现在时表示的动作，导致主句动作的必定发生，主句用一般现在时（主现从现） 4. if的双重用法if可以引导条件状语从句，意为“如果”，此时需注意“主将从现”的原则If it rains tomorrow, I wont come.if也可以引导宾语从句，意为“是否”，时态选用相对比较自由，不受“主将从现”原则的限定I dont know if it will rain tomorrow.Unless引导的条件状语从句unless引导的条件状语从句：unless
5、= if not “除非.否则, 如果不” Lets go out for a walk unless you are too tired. = If you are not too tied, lets go out for a walk. 我们出去散步吧，除非你太累 You will fail to arrive there in time unless you start earlier. =If you dont start earlier, you will fail to arrive there in time. 如果你不早点动身,你就不能及时赶到那儿。 Unless it ra
6、ins, the game will be played. = If it doesnt rain, the game will be played. 除非下雨,比赛将照常进行。 My baby sister never cries unless she is hungry. = My baby sister never cries if she isnt hungry. 我的妹妹不会乱哭，除非她饿了。 注意：unless引导的条件状语从句也要遵循“主将从现”，“主祈从现”及“主情从现”的规则。综合练习一、单选题( ) 1. I dont know if it _ tomorrow. Well
7、, if it _, the school sports meet will be canceled. A. will rain, will rain B. rains, will rain C. will rain, rains D. rains, rains( ) 2. We _ for a picnic if it _ rain this Sunday. A. will go, doesnt B. will go, wont C. go, doesnt( ) 3. I wonder if she _ me when_. A. calls, she arrives B. will call
8、, she arrives C. calls, will she arrive( ) 4. Could you tell me when Mr. Li _ in Daqing? Sure. When he _, Ill call you. A. comes, comes B. will come, comes C. comes, will come D. come, comes( ) 5. We plan to have a picnic tomorrow, so I wonder if _. A. will it rain B. it rains C. it will rain( ) 6.
9、If you close the door of sadness behind you, the door of happiness _ before you. A. opened B. have opened C. will open D. are opening( ) 7. Can you guess if Mike _ swimming this afternoon? I think he will go with us if he _ free. A. will go, is B. will go, will be C. goes, is D. goes, will be( ) 8.
10、I think its necessary for my daughter to have her own mobile phone, for I sometimes want to make sure if she _ home for dinner. A. come B. comes C. has come D. will come( ) 9. Im not sure if he _ in this exam. But if he _harder, he will do better. A. succeeds, worksB. will succeed, will work C. will
11、 succeed, works D. succeeds, will work( ) 10. Jeff _ the hospital if he feels better in a few days. A. leavesB. left C. will leave D. has left( ) 11. Do you know what time your uncle _Hangzhou tomorrow? At 2:00 p.m. I will meet him when he _ at the airport. A. gets to, arrives B. will get to, will a
12、rrive C. will get to, arrives D. gets to, will arrive( ) 12. Hi, do you know if Tom _ to my party next week? I think he will come if he _ free. A. will come, will be B. will come, is C. come, is D. come, will be( ) 13. Were not sure if it _ tomorrow. If it _, we wont go hiking. A. will rain, rains B
13、. will rain, will rain C. rains, rains D. rains, will rain( ) 14. It _ long _ we know the result of the experiment. A. will not be, before B. is, since C. will not be, until D. has been, after( ) 15. Its beyond doubt _it will _ later in the day. Take a raincoat with you. A. that, be rain B. whether,
14、 be rain C. that, be rainy D. if, have rain当堂练习一、单选题( ) 1. Do you know when _ your parents? I dont know. But if they_, I will tell you. A. will come, comeB. will come, will come C. come, will comeD. come, come( ) 2. Amy, do you know if Daniel _ to the farm with us tomorrow if it _? Sorry, Ive no ide
15、a. A. will go, will rainB. will go, rains C. goes, will rainD. goes, rains( ) 3. I hear there _ a talk on the history of China at the hall _ April 20th. A. will have, in B. will be, on C. is going to have, until D. is going to be, at( ) 4. Do you know when your mother _? I dont know. But if she _, I
16、ll tell you. A. will come, comesB. will come, will come C. comes, will comeD. comes, comes( ) 5. The radio says it _ a lot tomorrow. Thats too bad. It _ so often in summer in Suqian. A. will rain, rains B. rains, will rain C. will rain, is going to rain D. rains, rains( ) 6. Mum, do you know if Dad
17、_ a model plane for me? I think he will do if he _ free. A. will make, will be B. makes, is C. makes, will be D. will make, is( ) 7. Mike _ the good news to his mother as soon as he _ his mother after school.A. will tell; seesB. tells; seesC. tell; seeD. will tell; will see( ) 8. We will go for a pi
18、cnic_it is sunny tomorrow.A. whenB. whetherC. ifD. while( ) 9. Maria will spend time with her family as soon as she _ time. A. will haveB. haveC. hasD. had( ) 10. The traffic in Shanghai will become better if everyone the traffic rules. A. will obeyB. is obeyingC. obeyD. obeys( ) 11. If Mary late to
19、morrow，the teacher wont let her in. A. isB. will beC. beD. was( ) 12. I wont go to Lindas party unless . A. I will be invitedB. I am invitedC. I will not be invitedD. I am not invited( ) 13. James with the Greens the White Tower Park if it tomorrow. A. are going to; isnt rainyB. are going to; doesnt
20、 rainC. is going to; wont rainD. is going to; isnt rainy( ) 14. What will you do _ it doesnt rain tomorrow. Well have a picnic. A. untilB. becauseC. ifD. though( ) 15. Frank could we paint the room together tomorrow? Sure, if I _ free tomorrow. A. beB. will beC. amD. am going to be课后巩固( ) 1. Shall w
21、e go for a picnic tomorrow? If it rain. A. isntB. wontC. dontD. doesnt( ) 2. I will watch TV instead of swimming outside as soon as it tomorrow. A. rainsB. will rainC. rainedD. have rained( ) 3. If it_tomorrow , we shall go on foot.A. not rainB. dont rainC. rainD. doesnt rain( ) 4. My brother will d
22、o this job better if he _ how to use a computer. A. will knowB. knowsC. knowD. knew( ) 5. What are you going to do this weekend, Daming? I will have a picnic with my friend if it .A. rainsB. wont rainC. doesnt rainD. isnt rain( ) 6. Your aunt will walk the dog tomorrow morning. Yeah, unless bad weat
23、her _ her.A. stopsB. will stopC. to stopD. stop( ) 7. I will send you an emai1as soon as I _ in Australia.A. arriveB. arrivedC. am arrivingD. will arrive( ) 8. My sister has learned English .A. for twelve years agoB. since she was fourC. twelve years agoD. at the ago of four( ) 9. Dont worry about m
24、e, mum. Ill write to you as soon as I school. A. will get toB. arrive atC. will reach( ) 10. We will go camping if it _ tomorrow.A. wont rainB. doesnt rainC. didnt rainD. isnt raining( ) 11. Cindy will do a better job if she _ over and over again. A. will practiceB. practicedC. practicesD. has pract
25、iced( ) 12. It was not until she had finished all her work _home. A. did she returnB. that she returnedC. when she returnedD. that did she return( ) 13. I will go out for a walk after supper, if it _. A. didnt rainB. wont rainC. isnt rainingD. doesnt rain( ) 14. They will not go to the concert if it _tomorrow. A. will snowB. snowedC. snowsD. snow( ) 15. Ill go to the zoo if it _ tomorrow. Will you go with me? Sure. A. doesnt rainB. isnt rainingC. wont rainD. didnt rain参考答案综合练习1-5CABBC6-10 CADCC11-15 CBAAC当堂练习1-5 ABBAA6-10 DACCD11-15 ABCCC课后巩固1-5 DADBC6-10 AABBB11-15 CBDBA
