If引导的两种从句(宾语从句和条件状语从句)

1、重点、难点1. 含有 if 引导的条件状语从句的复合句中主从句的时态。2. If 引导的宾语从句与条件状语从句的区别。考情分析通常在单项选择、完形填空或补全、完成句子等题型中考查，分值约34 分。知能提升(一) 知识讲解 【认知讲解 】I. if 引导的宾语从句 if 引导宾语从句时，意思为：是否，从句的时态通常要和主句保持一致。 【例句】I want to know if he lives there. 我想知道他是否住在那儿。 He asked me if I could help him. 他问我是否能帮他。 【考查点】 if、 whether 引导的宾语从句的区别1. if 或 whe

2、ther 引导宾语从句时，作“是否”讲，常放在动词ask、 see、 say、know 和 findout 等后面。一般情况下，两者常可换用，在口语中多用if。【例句】Nobody knows whether / if it will rain tomorrow. 没有人知道明天是否下雨。Lucy asked whether / if they had a cotton sweater. 露西问他们是否有棉制的毛衣。2. if 或 whether 引导宾语从句时，要注意三个方面，即连词、语序和时态。 if 或 whether 既不能和 that 或其他连词(副词)同时使用，也不能省略。 【例句

3、】 我不知道他今天是否会来。误 I don 't know that if(whether) he will come here today. 正 I don 't know if(whether) he will come here today.他走过来看看猫是否出了毛病。误 He came to see what if (whether) there was anything wrong with his cat . 正 He came to see if (whether) there was anything wrong with his cat . if 或 whet

4、her 引导宾语从句时，虽具有疑问的意义，但其从句应用陈述句的语序。 【例句】Did you know the way to the hospitalThe old woman asked me.The old woman asked me if / whether I knew the way to the hospital. 老妇人问我是否知道去医院的路。if 或 whether 引导的宾语从句应和主句的时态保持一致。即主句为一般现在时，从句用 任一种时态；主句为一般过去时，从句则用过去时中的任一种时态。【例句】I don ' t know if (whether) he has

5、come here. 我不知道他是否来过这儿。Tom asked if (whether) I had read the book. 汤姆问我是否看过这本书。3. 只能用 whether 的情况 在动词不定式之前只能用 whether ： 【例句】I can ' t decide whether to stay. 我不能决定是否留下。在 whether or not 的固定搭配中 ：【例句】I want to know whether it' s good news or not.我想知道它是不是好消息。在介词后，只能用 whether ：【例句】His father is w

6、orried about whether he loses his work. 他的父亲担心他是否会失去工作。用 if 会引起歧义时：【例句】Could you tell me if you know the answer 这句话有两种意思：“你能告诉我你是否知道答案吗”或“如果你知道答案，请告诉我，好吗” 。 如用 whether 则可避免歧义。【考题链接】I don ' t know they could pass the exam or not.A. whyB. if C. that D. whether答案： D解题思路： 本题考查 if 与 whether 的区别，在 whe

7、ther or not 的固定搭配中通常只用 whether 。II. if 引导的条件状语从句1. 含义 条件状语从句是在复合句中作条件状语的句子。 表示假如有从句的动作发生就会有主句的动作发生，条件状语从句常由从属连词 if 引 导。【例句】You will catch the bus if you get up early. 如果你早起的话，就能赶上公共汽车。2. 类别主祈从现 ：主句是 祈使句 , 从句是由 if 引导的使用 一般现在时 的句子。【例句】If you want to go, please tell me. 如果你想去，请告诉我。 Print the photo if y

8、ou like it.如果你喜欢这照片就把它打印出来。 主将从现： 指 if 引导的条件状语从句用 一般现在时 ，主句用 一般将来时 。【例句】If it doesn 't rain tomorrow, we 'll go to the Great Wall. 如果明天不下雨，我们就会去长城。If you don 't get up early, you will be late for school. 如果你不早点起床，你上学就会迟到。3. if 引导的条件状语从句用法：（1）位置if 引导的条件状语从句， 既可放在主句之前也可放在主句之后。 当从句置于主句之前时，

9、常用逗号与主句隔开。【例句】You will catch the bus if you get up early.=If you get up early, you will catch the bus. 如果你早起的话，就能赶上公共汽车。（2）时态 应遵循主、从句时态呼应的原则。 当主句是一般现在时（包含祈使句和含情态动词 can, may, must 等的句子），从句也用 一般现在时。【例句】You must see the doctor if you are ill. 如果你生病了，你必须去看医生。If you want to go skating, wear warm clothes.

10、 如果你想去溜冰，穿上暖和的衣服。如果主句是一般将来时，从句必须用一般现在时。【例句】You will be late for school if you get up late. 如果你起晚了，你上学将迟到。If it rains tomorrow, we won' t go to the Great Wall.如果明天下雨，我们就不去长城了。（3）在 if 引导的条件状语从句中， 当主句是一般将来时时， 不能使用 be going to 结构， 而要用 will 。【例句】I ' ll help you with your English if I am free tomo

11、rrow. 如果明天我有空，我会帮助你学英语。（ 4）在 if 引导的条件状语从句中不能使用some，而要用 any。【例句】If you have any questions to ask, please come to my office. 如果你有问题要问的话，请到我办公室来。（5）同义句转换 if 引导的条件状语从句可转换成简单句，其方法如下：* 借助“祈使句 +and/ or+ 简单句”结构。其中 and 表示句意顺承， or 表示句意转折。 【例句】If you work hard, you ' ll pass the exam. =Work hard, and you &

12、#39; ll patshse exam. 如果你努力学习，你就会通过考试。If you don ' t hurry up, you ' ll be late.= Hurry up, or you ' ll be late. 如果你不快点，你将会迟到。* 借助介词 with 或 without 来转换。【例句】If you help me, I ' ll finish my job soon.=With your help, I ' ll finish my job soon. 如果你帮我，我将很快完成我的工作。If there is no water,

13、 fish may die. = Fish may die without water. 如果没有水，鱼可能会死。另外， if 从句还表示不可实现的条件或根本不可能存在的条件， 即一种虚拟的条件或假 设。从句多用一般过去时或过去完成时，表示对现在或过去的一种假设。【例句】If I were you，I would invite him to the party 如果我是你，我会邀请他参加聚会。I would have arrived much earlier if I had not been caught in the traffic 要不是交通堵塞，我会来得更早一些。4. 口诀： if 条

14、件句不一般，几个要点记心间； 条件句，放在前，逗号要放句中间。条件句表可能，主句多用将来时； 条件句表事实，主句常用现在时。III. If 引导的宾语从句和条件状语从句的区别if 引导条件状语从句时意为 “如果”，引导宾语从句时意为 “是否”，可用 whether 替换。 【例句】1） We will go out if it is fine tomorrow. 如果 明天天好，我们就出去。2） I don ' t knoifw t he train has arrived. 我不知道火车 是否 已经到达。 句 1） 中 if 引导的是状语从句。这个从句表示“条件” 。句 2）中 if

15、 引导的是宾语从句，充当谓语动词don' t know的宾语。【考题链接】ll tell youI don ' t know he will come tomorrow. he comes, I 'A. if; Whether B. whether; WhetherC. if; ThatD. if; If答案： D 解题思路： 第一个空处为宾语从句的引导词，用 if、 whether 都可以；第二个空为条件 状语从句的引导词，需用 if，综合考虑， D 项正确。（二）提分技巧1. 熟练掌握 if 引导的宾语从句与条件状语从句的特点。2. 熟知 if 引导的宾语从句与条件

16、状语从句引导词的区别。（三）即学即练I. 句型转换1. Do they want fried chicken He asked the boys.（ 改为宾语从句 ）He asked the boys they fried chicken.2. Was the watch made in Shanghai I don ' ktnow.(改为宾语从句 )I don ' ktnow the watch made in Shanghai.3. “ D oyou want to try something new”Tom' smother asked him.( 同义句转换 )

17、Tom' msother asked him to try something new.答案： 1. if / whether, wanted2. if / whether, was 3. if / whether he wantedII. 用括号中所给动词的适当形式填空1. If it (not rain)tomorrow, (let) us go shopping.2. Please (tell)me if you (go).3. If you (be)ill, you (have)to see the doctor.4. I (leave)for Beijing if it (n

18、ot snow) this afternoon.答案： 1. doesn't rain, let2. tell, go 3. are, have4. will leave, doesn 't snowIII. 将下列句子翻译成英语。1. 如果明天不下雨，我就和同学们去野餐。2. 如果周日你去购物的话，我就去。3. 如果你想减肥( lose weight )，就锻炼身体吧。4. 如果冬天来了，春天还会远吗5. 如果可能的话，我就去火车站接你。答案：1. If it doesn' t rain tomorrow, I will have a picnicm wy icthl

19、a ssmates.2. I will go shopping on Sunday if you do.3. Take some exercise if you want to lose weight.4. If winter comes, can spring be far behind5. If (it is) possible, I' ll meet you at the train station.下学期期中复习（一）一、预习新知Module 1-Module 5 重点基础知识二、预习点拨 思考问题一：能否先把这 5 个模块的重点单词、短语、语法整理一下 思考问题二：我们已经学

20、习了哪些语法哪些还是你比较薄弱的（答题时间： 45 分钟）、用所给动词的适当形式填空。1. If you (feel) tired, you (have) to have a rest.2. Where he (see) the film if he (have) time3. If there (be) fewer trees, there (be) more pollution.4. He (dress) more casually if he (not work) on weekends.5. If Marcia (live) alone, she (keep) a pet parrot

21、.6. Lana (buy) a new dress if the old one (be) out of style.7. The twins (fight) if they(argue).8. I (have) a bake sale if I (need) money for education.9. Peter (send) me a beautiful souvenir if he (tour) Spain.10. If Mr Green (say) I am hard- working, my parents (feel) glad.(go) to the beach if it

22、(not rain) this week.12. they (have) a match if the . teacher (be) busy13. He (write) a letter to his grandparents if he (get) his report card this week.14. If she (get) up late, she (not catch) the early bus.15. Peter (major) in English if he (pass) the exams in Peking University.二、完成句子(每空一词) 。1. 如

23、果你要过马路，不要乱跑。 around if you cross the road.2. 明天如果下雨的话，我们将呆在家里。We at home if it tomorrow.3. 如果你能说好英语的话，你就可以容易地与外国人交谈。If you can English well, you foreigners easily.4. 如果你对别人好，人们也会对你好。If you ' re nice to people, they to you, too.5. 如果学生不对考试如此担心的话，他们会更开心的。If students don' t worry about exams so

24、 much, they .6. 他如果电视看太多了，他的父母会不高兴。If he TV too much, his parents unhappy.7. 如果我们为他组织生日聚会，大家都会来的。Everyone if we a birthday party him.8. 如果明天不下雨，我会和你一起去公园的。If it tomorrow, I go to the park you.9. 如果他有空，他会帮助你的。If he , he you.10. 如果 Tom 考试不及格，他就没有机会上高中了。Tom have the to go to the senior high school if h

25、e theexams.三、同义句转换。1. Study hard, or you won' t pass the exam.If you study hard, you the exam.2. Take a taxi, and you' ll catch the train. you a taxi, you' ll catch the train.3. If you go to bed early, you won' t feel tired in the morning. early, you won' t feel tired in the morn

26、ing.4. If you don' t work hard, your teacher will probably be angry. , your teacher will probably be angry.5. Breathe deeply for one minute, and you' ll feel relaxed. you deeply for one minute, you relaxed.四、阅读下面的广告，然后用“ if., .will. ”的句式回答问题。 Travel BrochureCheap Cheap Cheap. Beijing for the

27、 weekend. 3D/ 2N. Book Now. Five Star Hotel Save 50%Four Star Hotel Save 40%Three Star Hotel Save 30%Book before December 31st. Breakfast Included.City Tour 50RMB. Visit the Great Wall 100 RMB.1. How much will you save if you stay at the Four Star Hotel2. How much will you save if you stay at the Th

28、ree Star Hotel3. What will happen if you book after December 31st4. How much will you have to pay if you want to go on the City Tour5. How much will you have to pay if you want to visit the Great Wall五、单项选择A. will goB. wentC. goD.going2. It will be a long time _ Peter his work.A. since, has finished

29、B. after, finishesC. when, will finishD.before, finishes3. What will father us from JapanA. takeB. bringC. carryD.make4. Weifang is famous _ kites.A. forB. toC. onD.with5. I her the answerif she me.A. can tell, will askB. will tell, will askC. would tell, askD. will tell, asks' ll have a great t

30、ime.1. If youto the party, you6. What are you going to do tomorrowC. won ' t rainD. doesn ' t rain We' ll go to the library tomorrow if it _.A. isn ' t rainB. rain7. Do you know when he will come back tomorrow Sorry, I don ' t know. When he back, I ' ll tell you.8. What will

31、you do if you _ to the old folks home visitA. goB. wentC. goingD.will go9. If I eat food, I' ll be very fat.A. too manyB. many tooC. too muchD.much too10. I ' ll give the book to him if he _ here next Sunday.A. will comeB. comesC. is comingD.cameA. comesB. will comeC. comeD. may come11. Ther

32、e an English film in our school tomorrow.A. is going to haveB. will haveC. is going to be D. has12. Could you tell us where A. will the next Olympic Games heldB. the next Olympic Games will be heldC. would the next Olympic Games be heldD. the next Olympic Games would be held13. When my mother returned last night, I a book.A. readB. am readingC.was readingD. am going to read14. What you _ w