最新人教版英语七年级下Unit12课本知识梳理及课后习题

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Words and expressions:

1Do you have to wear a uniform? Yes, we do.

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⑴have to 在本句中的意思是“必须，不得不”。

①have to 后接动词原形，当主语是第三人称单数时，用has to. I have to get up early every morning.

Tom has to stay at home to look after his sister. We have to clean the classroom after school.

②当have to 用于否定句或疑问句中时，要根据时态加助动词。 We don’t have to finish our homework at school. Does she have to go to school tomorrow? Yes, she does. ⑵区分must和have to

must 与have to 都有必须的意思，但must 强调主观看法，have to 比较强调客观需要，must 则不能。 I have to go home early this afternoon. We must clean our classroom every day.

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Words and expressions:

Practice your guitar every day.

①本句是一个祈使句，祈使句通常以动词原形开头， 用来表示

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命令，请求或劝告的句子。 Do your homework after school. Come to school earlier next time. Close the window, please.

祈使句的否定句在句首加Don’t 或Do not. Don’t wear hats in class. Don’t be late for school again. Don’t watch TV in the evening.

以let us 或 let’s 开头的祈使句表示建议做某事。 Let’s go to the mountains. Let us help you.

有时为了强调，在肯定结构前加do. Do come on time tomorrow.

②practice 的用法， practice 在美式英语中既可作动词，又可作名词， practice 在英式英语中是名词，动词是practise. practice 作动词时，既可作及物动词，又可作不及物动词。意思是“练习，实践”，作及物动词时，后面可接名词，代词或动名词作宾语。

I have to practice playing the piano every day. We must practice speaking English as often as we can. practice 作名词时，意思是“练习，实践，训练”。

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