Unit2 Healthy Lifestyle 动词不定式作主语课件-2023-2024学年高中英语人教版（2019）选择性必修第三册

动词不定式作主语 Look at the following sentences and pay attention to the italicised infinitives. Find more infinitives in the reading passage. In pairs, discuss their meanings and functions. 1. To change bad habits is never easy. 2. It took the surgeon three hours to finish my mother’s lung surgery. 3. To join the People’s Liberation Army, it is required for men to shave off their beards. 4. It was not polite to disturb your neighbours with loud music last night. The infinitive in each sentence functions as the subject of the sentence. 自主探究 阅读下列句子， 注意黑体部分的用法。 1.It takes three generations to make a gentleman． 2.What a relief it is for us to succeed in our experiment at last！ 3.It was careless of you to leave your umbrella on the train． 4.To do this is to cut the foot to fit the shoe． 5.To read without reflecting is like eating without digesting． 我的发现 （1） 所有黑体部分都是____________作主语。 动词不定式 （2）句1、2、3中黑体部分为____________作句子的真正主语，句中的it为 ______主语。 动词不定式 形式 （3）句4、5中直接用动词不定式作句子的______。 主语 3 探究点 动词不定式作主语 1.动词不定式作主语，谓语动词常用第三人称单数形式。 To see is to believe. 眼见为实。 To climb up the mountain road is easy while to go down the hills is hard. 上山容易下山难。 It is not easy to find your way to the town. 要找到去这个小镇的路并不容易。 4 2.动词不定式作主语时，其位置有以下两种： （1）将动词不定式置于句首。 To get there by bike will take us half an hour. 我们骑自行车到那儿需要半个小时。 5 ②It takes sb+some time+to do sth How long did it take you to finish the work？ 你花了多长时间来完成这项工作？ （2）用it作形式主语，把作真正主语的动词不定式后置，常用于以下句式中： ①It+be+名词+to do sth It's our duty to take good care of the old. 照顾好老人是我们的责任。 ③It+be+形容词+for sb+to do sth It is difficult for us to finish writing the composition in a quarter of an hour. 在15分钟内完成这篇作文对我们来说太难了。 ④It+be+形容词+of sb+to do sth It is stupid of you to write down everything the teacher says. 你将老师所说的话全部记下来是很愚蠢的。 在此结构中，形容词往往表示事物的性质，如：important, necessary 在此结构中，形容词往往表示人物的性格和特征，如：kind, impolite V-ing 一般性的 抽象的 重复性 To do 一次性的 具体的 将要发生 注意： Clearing the blackboard is an easy job. To clear the blackboard is your job today． 8 融会应用 单句填空 （1）It took