八年级英语语法复习if宾语从句和条件状语从句课件

Grammar

语法1:正确使用that, if/whether(是否), who, why 等疑问词引 导的宾语从句。 语法2:if(如果)引 导的条件状语从句

什么是宾语从句？在复合句中做宾语成分的句子叫宾语从句。

宾语从句的分类、引导词和语序

原句式

引导词

从句语序

陈述句 一般 疑问句特殊 疑问句

that

不变

whether 改为陈述句 /if 语序 特殊 疑问词

改为陈述句 语序

宾语从句的时态

主句 一般 现在时

从句 保留原来句子的时态 或根据实际情况而定一般现在时 → 一般过去时 现在进行时 → 过去进行时一般将来时 → 过去将来时

一般 过去时任一时态

现在完成时 → 过去完成时若表客观事实、普遍真理及自然现象用 一般现在时

注：that 在句中无词汇意义，在从句中不能充当成分，在口语当中往往省略 e.g. he will be back in an hour (一小时后他会回来) 1. I hear (that) _______________________. he missed us very much (他非常想念我们) 2. He said (that) ______________________. the earth moves around the sun 3. The teacher told us (that) ___________________________.

(地球围着太阳转)注意：当从句是客观真理的时候，无论主句什么时态，从 句一律用一般现在时

由从属连词whether, if 引导的宾语从句

e.g. if (whether) he will go to the park with us 1. I want to know __________________________________.(他是否跟我们一起去公园)

2. Ask him _____________________ whether (if) he can come. (他是否能来) 3. I don’t know ___________________________. (是否要下雨) whether it is going to rain or not

当句末为or not时，引导词只能用whether而不能用if.

If 与whether 的区别1. I don’t know _____ he will come or not. 与or not 连用只能用whether 2. I don’t care of ______ he is handsome. 介词后只能用whether 3. He wondered ______ to stay here the next week.

与to do 不定式连用只能用whether 4. ____ he will come is not decided.作主语只能用whether

if (如果)引导的条件状语从句:用法：

1. 如果主句是祈使句，从句要用一般现在时。 Don’t go and play football if you don’t finish your homework. Please call me if he comes next Sunday.

2. 如果主句是一般将来时， if从句则用一般现在时。 If it rains(从句), I will stay at home. I’ll go with you if you don’t want to go alone(从句).3.如果主句含有must, may, can 等情态动 词，if从句也要用一般现在时。 If you drive too fast, you may have an accident. You must stop if the traffic is red.

Complete the sentences.1.If you want ____ (want) to listen to music,choose _____ (choose) a CD. get 2.If you ___ a good buy(buy) a new camera, ____(get) one. ’t come (not come) on, wait 3.If the lightdoesn ___________ ____ (wait) for one minute. 4.If it ___________ doesn’t work

(not work) , _____ wait (wait) a minute and then _____(try) again. try ’t know (not know) how to use the 5.If you don ________ camera, read ____ (read) the instructions.

Fill in the blankets with the proper formwill stay 1.If It______ rains (rain) tomorrow, I ______(stay) at home. 2.You may ______ pass (pass) the exam if youstudy ___ (study) hard. press 3. If you want to record, ________(press) the red light. was 4.He asked us if everybody ____(be) here.

Have a try

用括号内所给词的正确形式填空

1.If the rain _______(stop) tonight, we will go to the stops cinema. 2.I’ll buy a computer if I ______(have) enough money. have won’t get 3.You _________(not get) nervous if you _____(do ) do enough exercise. is (be) kind to me , I __________(not won’t argue 4.If she ____ argue) with her.

will come 5.I want to know if he _________(come) tomorrow, ifcomes he _______(come), I __________(give) the massage will give to him.

summary

if 条件句不一般, 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， 主将从现不一般； 条件句表事实， 主句常用现在时 If还有“是否”意 , 宾语从句放后边

Thank you ,and have a good day.