2.2 unit 2 Learning about language grammar语法动词不定式做主语-高二英语同步精品课件+课后习题（人教版2019选择性必修第三册)

Unit 2 Healthy Lifestyle Period 2 Learning about language 1 动词不定式作主语 Infinitives as the subject 1.Enable the Ss to master the usage of the infinitive of the verb as the subject。 2.Enable the Ss to use the relevant grammar flexibly and authentically in the real situation. 3 (1)However,during this period，it can be easy for some of them to form bad habits. (2)To prevent harmful habits like these from dominating a teenager’s life is essential. (3)To change bad habits is never easy. (4)After all,it is not easy to break bad habits. 以上句子中动词不定式都是作 .句(1)和句(4)中it作 ，真正的主语是后面的 。 主语 形式主语 动词不定式 感知原文 1.不定式作主语通常位于句首，谓语动词用单数。 To obey law is everyone’s duty.遵纪守法是每个人的职责。 To get up early is necessary. 早起是必要的。 To learn a skill is very important for everyone in society.  学习一项技能对社会上的每个人都很重要。 To look after these naughty boys is really difficult. 照看这些淘气的男孩真的很难。 动词不定式作主语的用法 5 2. 动词不定式与疑问词who, whom, whose, what, which, when, where, how等连用构成不定式短语，也可作主语。 How to use