Unit 2 Discover useful structures-高中英语人教版（2019）选择性必修第三册.pptx

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1、Period 3 Discovering useful structuresThe infinitive of the verb used as the subjectUnit 2 Healthy Lifestyle 单元语法自我探究Look at the following sentences and pay attention to the italicized infinitives.Find more infinitives in the reading passage,and tell their meanings and functions.1.To change bad habi

2、ts is never easy.2.It took the surgeon three hours to finish my mothers lung surgery.3.To join the peoples Liberation Army,it is required for men to shave off their beards.4.It was not polite to disturb your neighbors with loud music last night.主语主语主语主语主语主语目的状语目的状语动词不定式作主语时，谓语动词用单数。To look after the

3、se naughty boys is really difficult.To get up early is necessary.To learn a skill is important for everyone in society.To change bad habits is never easy.It作形式主语，动词不定式作真正的主语放在句末。It took the surgeon three hours to finish my mothers lung surgery.基本用法Observe Observe and Discover1.It isnt right to talk

4、like that.2.Its difficult to master English.3.Its hard for me to answer the question.4.It is important to learn a useful skill.Discover 1.1.以上以上句子的真正主语都是句子的真正主语都是_，但都，但都使用使用it作作形式主语形式主语；2.2.以上句子的表语都是以上句子的表语都是_。动词不定式动词不定式形容词形容词Find more infinitives in the reading text.1.it can be easy for some of the

5、m to form bad habits.2.After all,it is not easy to break bad habits.3.动词不定式在句中做主语，有时为了保持句子的平衡，动词不定式在句中做主语，有时为了保持句子的平衡，避免头重脚轻，避免头重脚轻，常用常用it做形式主语做形式主语，而，而真正的主语放在句真正的主语放在句子末尾。子末尾。Their meanings and functionsFind and DiscoverGroup Work不定式作主语，it 做形式主语的常见结构：1.It is+adj.+(for sb)to do It is easy for me to

6、learn how to drive.2.It is+adj.+(of sb)to do It is clever of you to apply for the position.3.It is+n.+to do sth(an honour,our duty,a pity,a shame)It is our duty to take care of you.4.It takes/took sb some time to do sth.It takes me half an hour to do my housework.It is+adj.+(of sb)to do1.1.对我来说对我来说每

7、天读英语是很重要的。每天读英语是很重要的。2.2.你真是太好了，能帮你真是太好了，能帮我学英语。我学英语。3.3.能帮助你是我的荣幸。能帮助你是我的荣幸。4.4.我每天花我每天花1515分钟读英语。分钟读英语。Translation It is very kind of you to help me learn English.It is+adj.+(for sb)to doIt is+n.+to do sth(honour,duty,pity)It takes/took sb some time to do sth.It takes me 15 minutes to read English

8、 everyday.It is my honour to help you.It is important for me to read English everyday.It is important for me to read English everyday.It is very kind of you to help me learn English.It is+adj+for sb to do 表示事物的特征特点表示事物的特征特点(adj:easy,difficult,comfortable,pleasant,light,dangerous,tiresome,interesting

9、,heavy,fit)(adj:kind,good,nice,wise,unwise,clever,silly,stupid,foolish,careless,rude,polite,naughty)It is+adj+of sb to do 表示人物的性格品德表示人物的性格品德客观客观主观主观4.It is important _ Tom to get that job.5.It is kind _ you to help me with my work.1._(talk)with him is a great pleasure.2._(help)others is our duty.To

10、talkTo help=It is our duty to help others.forof3.It is easy_ the students to read.Practicefor把句2改为It作形式主语的句子1.To improve peoples lives _ an important task for our government.3.To be a good doctor _(need)years of hard work.2.Its silly _ you to give up such a good chance.4.To get the work done as quic

11、kly as possible _ what I wanted.isofneedsis3.如果要说明不定式表示的动如果要说明不定式表示的动作是谁做的，作是谁做的，可以在不定式前加一个由可以在不定式前加一个由 for/of for/of 引起的短语引起的短语,构成构成_。2.不定式作主语时,可以用it作_.it作形式主语的几个句型是？It is+adj+for sb to do It is+adj+of sb to do（修饰人品形容词）（修饰物的形容词）1.单个不定式作主语，谓语动词_单数形式主语不定式的复合结构SummaryJoin the words to make full senten

12、ces using the infinitive.1.important/avoid/passive cigarette smoking.2.will take/nutrition specialist/a balanced diet menu/make/an hour/for you.3.useful/turn to/fitness consultant/for advice4.illegal/dangerous/take/drugs5.harmful/skip breakfast/oftenHomeworkExcersie 2 P171.important/avoid/passive ci

13、garette smoking.It is important avoid passive cigarette smoking.2.will take/nutrition specialist/a balanced diet menu/make/an hour/for you.It will take a nutrition specialist an hour for you to make a balanced diet menu.3.useful/turn to/fitness consultant/for advice It is useful to turn to fitness consultant for advice.4.illegal/dangerous/take/drugsIt is illegal and dangerous to take drugs.5.harmful/skip breakfast/oftenIt is harmful to often skip breakfast.HomeworkThank you!