Unit2 不定式做主语课件-2022-2023学年高中英语人教版（2019）选择性必修第三册

Discover useful structures UNIT 2 HEALTHY LIFESTYLE 1. Master the use of to do as subject in this unit. 2. Students can use “to do” flexibly in their daily life. Learning Objects 动词不定式 1 动词不定式作主语 ( 1)用作主语的动词不定式及其短语常出现在谓语动词之后,而句首用形式主语it 代替。 It is not right for people with the virus to go to public places. 携带这种病毒的人去公共场所是不对的。 ( 2)不定式作主语位于句首常出现在正式文体中,单个不定式作主 语,谓语动词用单数形式。 To get enough protein each day is beneficial to our health. 每天摄取足够的蛋白质对我们的健康有益。 (3)常用句型: ①It is + adj. + for /of sb. + to do sth. 形容词表示事物或行为的特点或性质,介词用for, 如good,easy, difficult,possible,necessary。 形容词表示人的品格或特点,介词用of, 如kind,polite,impolite, rude,foolish。 It is necessary for us to prevent the war breaking out. 我们有必要防止战争爆发。 It is too impolite of you to speak to an outstanding teacher like this. 你这样对一位杰出的老师说话太无礼了。 ②It +be+ 名词+to do sth. 做某事是…… It’s my duty to take good care of my younger sister. 照顾好我的妹妹是我的责任。 It must be great fun to fly to the moon in a spaceship. 乘宇宙飞船飞往月球一定很有趣。 ③It takes sb. some time to do sth. 做某事花费某人多长时间 It took me more than an hour to do my homework yesterday evening. 昨天晚上我做作业用了一个多小时。 单句语法填空 (1)Sometimes it’s better (remain) silent. (2)Although is a hard task to protect our environment,we can’t help but go ahead. (3) (control) the air pollution is necessary. (4)It was foolish him to endanger his life in that way. (5)Don’t you think it is rude him to ask a lady her age? (6)It is difficult him to live on such a small salary. to remain it To control/Controlling of of for 完成句子 (7)I don’t think (你问……是不礼貌的) how long the interview will last. (8) (保卫…… 是我们的职责) the country against its enemies. (9) ( …… 花了我半个小时)to wash the clothes. it is impolite of you to ask It’s our duty to defend It took me half an hour 2 疑问词 + 不定式 (1)可用于该结构的疑问词 疑问代词:who,whom,what,which 疑问副词:when,where,how (2)常接该结构的动词:know,see,decide,tell,ask,consider,explain,learn,wonder (3)该结构的句法功能:主语、宾语和表语 How to construct the theoretical framework is very important. 怎样构建理论框架很重要。(作主语) The question is when to start developing such a vacc