UNIT 2 Section Ⅱ Learning About Language（Word教参）-【优化指导】2023-2024学年新教材高中英语选择性必修第三册（人教版2019）

Section Ⅱ　Learning About Language 动词不定式作主语 [对应学生用书P43] [观察] 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，even with many attempts. 4．After all，it is not easy to break bad habits. 5．To make choices about myself is within my own power. 6．And if that's true for me，then it might truly be possible to change the world for the better. [探究] 1．句中加黑部分均为动词不定式作主语。 2．句2、3、5的谓语动词都是单数。 3．句1、4、6中加黑部分为句子的真正主语，句中的it为形式主语。 1．思考什么情形下常用动词不定式作主语。 2．思考动词不定式作主语的常见句式结构。 一、动词不定式作主语的概念 [感知] 1．To know something about English is one thing；to know English is quite another. 懂一点英语是一回事；完全掌握英语是另一回事。 2．It is impossible to learn a foreign language without making painstaking efforts. 想不下苦功就能学会一门外语是不可能的。 [探究] 1．句1中动词不定式短语直接作主语。 2．句2中It作形式主语，真正的主语(动词不定式短语)后置。 [归纳] 不定式作主语，表示具体的、一次性的或将来的动作；在很多情况下，人们通常用it作为形式上的主语，而把动词不定式移到谓语之后，使句子结构显得平稳一些。 [即练] 单句填空/完成句子/句型转换 ①To jump(jump) out of the window is dangerous. ②As we all know，it is good for your health to stop smoking. ③我很荣幸邀请你来中国。 It would be a great honor for me to invite you to come to China. ④English is not so easy to learn well. →To learn English well is not so easy.(动词不定式作主语) →It is not so easy to learn English well.(it 作形式主语) 二、动词不定式作主语的用法 (一)动词不定式直接作主语 [感知] 1．To love and to be loved is the greatest happiness one can get. 爱和被爱是一个人能得到的最大幸福。 2．To get up early is necessary. 早起是必要的。 3．To save time is to lengthen life. 节约时间就是延长生命。 [探究] 1．以上句子中加黑的动词不定式(短语)在句中直接作主语(成分)，谓语动词采用第三人称单数形式。 2．句3的主语是动词不定式短语，作表语的也是动词不定式。 [归纳] 1．动词不定式作主语通常位于句首，表示具体的某次动作，谓语动词采用第三人称单数形式。 2．动词不定式作主语时，若其后需要动词作表语，则作表语的动词也使用不定式形式，即保持形式一致(To do ...is to do ...)。 不定式作主语与动名词作主语的区别 一般来说，动词不定式作主语，表示具体的、一次性的或将来的动作；动名词作主语，表示一般的、泛指的或习惯性的行为。但是在多数情况下无明显区别。如： To see is to believe.＝Seeing is believing. 眼见为实。 [即练] 单句填空/完成句子/一句多译 ①To teach you the uses of the infinitive is(be) my job today. ②To look(look) after the safety of the community is his r