Unit 2 Healthy Lifestyle Discover Useful Structures课件 -2023-2024学年高中英语人教版（2019）选择性必修第三册

Unit 2 Healthy lifestyle Discover useful structures To-infinitive as the subject Learning Objects: 1. To know the different forms of the infinitive; 2. To master the use of the Infinitive as subject; 3. To use the Infinitive as subject in the specific context correctly. 2 Lead-in Pay attention to the sentences 3 It is difficult for me to get up early. It is kind of you to help me! To get up early is difficult for me . To help me is kind of you ! to do 作主语 Lead-in 4 直接放在________作主语； 为了保持句子平衡，用________作形式主语，放在句首，把真正的主语 — 动词不定式置于句后； 和_________构成“疑问词+to do”短语作主语。 句首 it 疑问词 动词不定式作主语用法有三个： Presentation Presentation Observe To see is to believe. To get good grades requires a lot of hard work. To learn a skill is very important for everyone in society Discover 1.不定式作主语通常位于______，表示具体的某次动作，谓语动词用______。 句首 单数 6 To look after children is her job today. 她今天的工作是看孩子。 Looking after children is her work. 她的工作是照顾孩子。 Compare the two sentences below and tell the difference in meaning. Summary不定式作主语和动词-ing形式作主语的区别： 动名词作主语表示_______________的行为;不定式作主语表示 _________________________ 动作。 经常性或习惯性 具体的、一次性的或将来的 1. ______ (do) morning exercises regularly is good for your health. 2. It feels really good ______ (do) morning exercises today. Doing to do Presentation 2. 当主语较长，谓语较短时，常用it作形式主语放在句首，而将真正的主语—不定式放到谓语的后面。 It is not right for people with the virus to go to public places. It was not polite to disturb your neighbours with loud music last night. To join the People’s LiberationArmy , it is a rule for men to shave off their beards. It took the surgeon three hours to finish my mother’s lung surgery. Presentation 8 Observe It is interesting to play with snow in winter. It’s important for us to keep the water clean. It’s very kind of you to help me. Discover 以上句子的表语都是______。 形容词 it + be + adj + (逻辑主语) + to do sth Presentation It is necessary for you to change your job. It’s difficult for us to learn English well. It was silly of you to give up such a good chance! It’s very kind o