1、初中英语初中英语if引导的条件状语从句引导的条件状语从句主讲人：主讲人：单位：单位：eg:如果我有足够的钱，我就去环游世界If 引导条件状语从句 定义：定义：if “如果如果,假如假如”它引导的句子表示某事发生所需的它引导的句子表示某事发生所需的条件，即条件，即“在在条件下，某事才能发生条件下，某事才能发生”，在句子中充当状语，在句子中充当状语，因此称之为条件状语从句。因此称之为条件状语从句。If I have enough money,I will travel around the world orI will travel around the world if I have enoug
2、h money_if Im ill.I will see a doctorIf Im late,_.I will say sorry 位置：从句可放在主句之前或之后，但是放位置：从句可放在主句之前或之后，但是放在主句之前须有逗号隔开，放在主句后则不在主句之前须有逗号隔开，放在主句后则不用用 If it rains tomorrow,I_.will watch TV at homeIf it _ tomorrow,_.hell play basketballdoesnt rain用法：1.如果主句是一般将来时，从句则用一般现在时（主将从现）。如果主句是一般将来时，从句则用一般现在时（主将从现）。
3、If it rains（从句），I will stay at home.Ill go with you if you dont want to go alone（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（主情从现）。一般现在时（主情从现）。If you drive too fast,you may have an accident.You must stop if the traffic is red.If you finish the homework，you can go home 如果你作业做完了就可以回家了。如
4、果你作业做完了就可以回家了。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。如果你想减肥，你必须少吃面包。3.如果主句是祈使句，从句同样要用一如果主句是祈使句，从句同样要用一般现在时（主祈从现）。般现在时（主祈从现）。Dont go and play football if you dont finish your homework.Please call me if he comes next Sunday.4.如果if引导的条件状语从句说的是客观事实客观事实或者是普遍规律普遍规律的话，从句和主
5、句都用一般现在时eg.If you drop a glass,it breaks.If you heat ice,it meltsif的反义词：的反义词：if.not.=unless,意思是：意思是：“如果不，除非如果不，除非”I wont go there unless I hear from you.(同义同义句句)I wont go there _ I _hear from you.if dont I wont go to the party if I am not invited.(同义同义句句)I wont go to the party_ I am invited.unless变换
6、：变换：1.有有if引导的条件状语从句的复合句中，当主句和从句的引导的条件状语从句的复合句中，当主句和从句的主语均为主语均为you时，可转换为时，可转换为“祈使句祈使句+and/or+一般将来时的句子一般将来时的句子”You can pass the exam if you work hard.-，and you will pass the exam.If you dont hurry up,you will be late again.Hurry up,-you will be late again.Work hardor2.借助介词借助介词with 或或without来转换。来转换。例如例
7、如:If you help me,Ill finish my job soon.-,Ill finish my job soon.如果你帮我，我将很快完成我的工作。如果你帮我，我将很快完成我的工作。If there is no water,fish may die.Fish may die -.如果没有水，鱼可能会死。如果没有水，鱼可能会死。With your helpwithout water 注意事项注意事项 1.在在if引导的条件状语从句中，当主句是一般将引导的条件状语从句中，当主句是一般将来时时，不能够使用来时时，不能够使用be going to结构，而要用结构，而要用will。例如：
8、例如：Ill help you with your English if I am free tomorrow.如果明天我有空，我会帮如果明天我有空，我会帮你学英语。你学英语。2.在在if引导的条件状语从句中不能够使用引导的条件状语从句中不能够使用some，而要用而要用any。例如：例如：If you have any questions to ask,please come to my office.如果你有问题要问如果你有问题要问的话，请到我办公室来。的话，请到我办公室来。练习：练习：1、如果明天不下雨，我就和同学们去野餐。、如果明天不下雨，我就和同学们去野餐。2、如果你起来晚了，你上学将
9、迟到。、如果你起来晚了，你上学将迟到。3、如果你想节约能源，你应该骑自行车。、如果你想节约能源，你应该骑自行车。4、如果朋友有麻烦，我们应该尽力帮助他们。、如果朋友有麻烦，我们应该尽力帮助他们。If it doesnt rain tomorrow,I will have a picnic with my classmates.If you get up late,youll be late for class.You should ride your bike if you want to save energy.If our friends have troubles,we should t
10、ry ou best to help them.More practice1.If you _(drop)a glass,it _(break).2.He _(fail)in the exam if he _ (not study)hard.3.Unless you _(leave)now,you _(be)late.4.We _(have)a barbecue unless it _(rain).5.If you _(cool)water,it _(turn)into ice.6.Hurry up,or you will miss the bus._ you dont hurry up,yo
11、u _ catch the early bus.7.Study hard,or youll miss fall behind._ you study hard,you_ fall behind.8.If you dont put on your scarf,youll catch cold.Put on your scarf,_ youll catch cold.9.The insurance company would pay him 2 million yuan if the vase was stolen.The insurance company _ pay him 2 million
12、 yuan _ the vase was stolen.10.I dont know if it_ tomorrow.If it _,I wont go shopping.(rain)dropbreakswill faildoesnt studyleavewill bewill haverainscoolturnsIfwontUnlesswill orwontunlesswill rainrainsHave a try 用括号内所给词的正确形式填空1.Im sure if he _(go)to the party,he_ (have)a great time.2.If the rain _(s
13、top)tonight,we will go to the cinema.3.Ill buy a computer if I _(have)enough money.4.You _(not get)nervous if you _(do)enough exercise.5.If she _(be)kind to me,I _(not argue)with her.6.I want to know if he _(come)tomorrow,if he _(come),I _(give)the massage to him.7.If you _(pay)more attention to tha
14、t,he _ (not get)injured.goes will have stopshave wont getdo iswont argue comes comes will give pay wont get8.Mr Li will be mad if we _(break)the rules.9.If it _(be)cloudy,they _(not go)there by air.10.Please let us know if he _(arrive)tomorrow.Please let us know if he _(arrive)tomorrow.11.Shall I say“Hello”when the foreigner _(come)into the classroom?12.Hell get better grades if he _(study)hard.13.If you work really hard,you _(be)famous and rich.break is wont go will arrive arrives请告诉我们他明天是否会来。如果他明天来的话请告诉我们。comesstudieswill be表表是否，是否，用用将来将来时态时态表表如果，如果，用用一般现在一般现在时态时态
