Unit 2 Healthy Lifestyle Discover useful structures 不定式作主语课件-2023-2024学年高中英语人教版（2019）选择性必修第三册

语法精讲 Unit 2 1 Teaching objectives: By the end of this period, you will be able to… 1.master the usage of the infinitive as subject. 2.use the relevant grammar flexibly and authentically in real situation. 3.understand the difference between the infinitive as subject and V-ing form as the subject. Pay attention to the sentences Lead-in 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 ! Lead-in ⁎The infinitive in each sentence functions as the subject of the sentence. Observe To see is to believe. To get up early is necessary. 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 Learning Observe ________ to handle the rubbish is the question. ________ to go for dinner has not been decided. Discover 1.________ 和动词不定式构成不定式短语作主语 2.可用于该结构的疑问词 疑问代词: 疑问副词: 疑问词 who,whom,what,which Learning How Where when,where,how 1.When and where________ (vote) hasn’t been decided. 2.____________（何时装修） the house hasn’t been decided When to decorate to vote To work out the problem is not easy. =It’s not easy to work out the problem. It is interesting to play with snow in winter. It is terrible to see the ship sinking into the sea. Learning 当主语较长，谓语较短时，常用_____________放在句首, 而将真正的主语—________________________。 it作形式主语 不定式放到谓语的后面 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 Learning it + be + adj + (逻辑主语) + to do sth 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 of you to say so. Learning 若adj. “描述人的品格、特点”, 用of,如 kind, nice, wise, silly, polite, impolite, friendly, foolish, clever; 若adj.“描述事或行为的特征”, 用for,如easy, hard, difficult, possible, important, impossible, necessary,good, bad, exciting, interestin