1、1Adverbial Clause of Conditionif 引導的條件狀語從句引導的條件狀語從句& &賓語從句賓語從句-復習課復習課2She is doing her homework.If you are hard-working, you will get good grades.She gets good grades.3If you play computer games on weekdays ,youll be very tired in classyour parents will be sad.you wont get good grades.your e

2、yes will be poor41) 條件狀語從句通常由if或或unless(=if not)引導，從句中常用一般時代替將來時一般時代替將來時，即if或unless后的句子謂語用一般現在時。但是，主句則通常用將來時，情態動詞或祈使句。 時態主將從現時態主將從現主句一般將來時，主句一般將來時，從句一般現在時從句一般現在時51. 如果主句是一般將來時，從句則用一般現在時。如果主句是一般將來時，從句則用一般現在時。 If it rains（從句），（從句）， I will stay at home. Ill go with you if you dont want to go alone（從句）（

3、從句）. 2.如果主句含有如果主句含有must, may, can 等情態動詞，從句也要用等情態動詞，從句也要用一般現在時。一般現在時。 If you drive too fast, you may have an accident. You must stop if the traffic light is red.3. 如果主句是祈使句，從句同樣要用一般現在時。如果主句是祈使句，從句同樣要用一般現在時。 Dont go and play football if you dont finish your homework. Please call me if he comes next Su

4、nday. if條件狀語從句結構及時態條件狀語從句結構及時態Revision6 If 引導條狀語從句時，從句中用一般現在時代替一般將來時。1. If he _(go) to the movies,he wont finish his work.goes 2. If I _(become) a doctor,I can help others. become3. If we _(have )time, we will go to the park tomorrow.have4.如果你去，如果你去， 我也去。我也去。If you go,I will go.5.如果明天下雨，請帶雨衣如果明天下雨，請

5、帶雨衣。 raincoatPlease take a raincoat if it rains.7If you are free this weekend,what will you do ?If I am free ,sleepwatch TVplay computer gamespractice8If you want to get good marks,do what? Dont do what? If you want to get good marks, _. If you want to get good marks, dont _. study hard listen to te

6、achers carefully. do homework by yourself. copy your homework. talk in the class cheat in the exams9If 條件句的替代形式：條件句的替代形式：（1）祈使句祈使句 + and/or + 陳述句陳述句（謂語動詞通常用將來時態（謂語動詞通常用將來時態）。其中，）。其中，and表示句意順承；表示句意順承；or表示轉折，意為表示轉折，意為“否則否則”。e.g. If you work hard, youll pass the exam easily. = Work hard, and youll pass

7、 the exam easily.If you dont work hard, youll fall behind others. = Work hard, or youll fall behind others.10（2）用介詞）用介詞with, without的替代形式：的替代形式： e.g. If there is no water, the fish may die. = Fish may die without water. If you help me, Ill finish my task on time. =With your help, Ill finish my task

8、on time.11If 在賓語從句中翻譯為在賓語從句中翻譯為“是否是否”If 在條件狀語從句中翻譯為在條件狀語從句中翻譯為“如果如果”Ill go to see you if I am free next week. I want to know if he is a teacher.whether1. if 在句中的含義不同在句中的含義不同122. if 在從句中的位置不同在從句中的位置不同If 引導的賓語從句放在主句之后；而引導的賓語從句放在主句之后；而if引引導的狀語從句可放在主句之前也可放在主導的狀語從句可放在主句之前也可放在主句之后句之后= If it doesnt rain, I

9、 will go out tomorrow.I will go out tomorrow if it doesnt rain.I dont know if the train has arrived. If 引導的條件狀語從句放于句首時多用逗號隔開；引導的條件狀語從句放于句首時多用逗號隔開；而而if引導的賓語從句則不能。引導的賓語從句則不能。133. 時態要求上有區別時態要求上有區別If 引導條件狀語從句的時態為一般現在時引導條件狀語從句的時態為一般現在時 記住記住“主將從現主將從現” 1.I want to know if there a sports meeting next month.

10、doesnt rainwill be2.If it doesnt rain ,well go outIf 引導的賓語從句的時態由主句及本身時引導的賓語從句的時態由主句及本身時態決定；態決定；141. Can you tell me if she can come to the meeting ?2. She will not go there if it is rainy tomorrow.3. I cant guess if she will be angry .4. If we help each other , we will get good results .151 If I _(n

11、ot understand）, I will ask my teacher for help . If I _(copy ) your homework , I will cheat myself . I dont know if it _ (rain) tomorrow.2 My teacher asked me if I _ (finish) my homework already. dont understand copy will rain had finished16if的用法的用法2.引導條件狀語從句：引導條件狀語從句：譯為譯為“如果，假如如果，假如”(1) if從句從句+祈使句祈使句(2) if從句從句+主句（一般將來時）主句（一般將來時）(3) if從句從句+主句（含有情態動詞）主句（含有情態動詞） 1.引導賓語從句引導賓語從