(
课件网) Period Ⅲ Grammar———动词不定式作主语 UNIT 2 HEALTHY LIFESTYLE 图解 语法脉络 感知 语法规律 /////// 1 2 4 /////// /////// 精讲 语法知识 3 /////// 跟踪 落实检查 1 图解 语法脉络 2 感知 语法规律 观察下面的句子,并感知动词不定式作主语的基本用法。 1.However,during this period,it can be easy for some of them to form bad habits. 2.To change bad habits is never easy,even with many attempts. 3.After all,it is not easy to break bad habits. 4.To know something about English is one thing;to know English is quite another. 3 精讲 语法知识 动词不定式是非谓语动词的一种,没有人称和数的变化,在句中可以作主语(有名词和代词的作用),通常表示具体的、特定的行为。 一、动词不定式作主语的基本用法 1.动词不定式表示某一次具体的、特定的或有待实现的动作。 To promote the elderly people’s welfare is the purpose of the project. (2022·新高考Ⅰ卷) 该项目的目的是提升老年人的福利。 [名师点津] 表示单一概念的动词不定式作主语时,谓语动词用单数形式。 To have a positive attitude is wise when we are let down.(建议信) 当遭遇挫折时,怀有积极的态度是很明智的。 2.it作形式主语,真正的主语(动词不定式)后置,特别是动词不定式短语较长时。常用于下列句式中: (1)It+be+名词(词组)+to do... But no matter when you travel,it’s a good idea to make your reservations at least 90 days in advance.(建议信,2023·浙江1月卷) 但无论你何时旅行,最好至少提前90天预订。 (2)It+be+形容词+(for/of sb)+to do... A few days later,I came back with my first jars of zero waste groceries,and my dad commented on how silly it was for me to carry jars everywhere. (2023·浙江1月卷) 几天后,我带着第一罐零废弃杂货回来了,我父亲评论说,我到处带着罐子是多么愚蠢。 [名师点津] ①该句式结构中for sb前常用表示事物的特征、特点的形容词,如easy, hard, difficult, interesting, impossible等。 It is not appropriate for a student to litter and scribble.(倡议书) 学生乱扔垃圾和乱涂乱画是不合适的。 ②of sb前一般用表示人物的性格、品德及主观感情或态度的形容词,如good, kind, nice, clever, foolish, right等。 It’s very kind of you to help me with the work. 你帮助我做这项工作,真是太好了。 (3)It takes/costs/requires/makes sb/sth...to do... If it takes the train 53 seconds to travel one mile,you’re going 67.92 mph. (2023·浙江 1月卷) 如果火车行驶一英里需要53秒,你的时速是67.92英里。 3.“疑问词+动词不定式短语”作主语 How to get along well with others is the second thing you should learn.(建议信) 如何与别人友好相处是你应该学会的第二项。 How to use the computer is a question. 如何使用计算机是个问题。 二、 动词不定式与动名词作主语的区别 1.动名词作主语通常表示抽象动作;而动词不定式作主语表示具体动作。 Miss Johnson thinks being with children is the best part of her job.(抽象,2023·浙江1月卷) 约翰逊小姐认为和孩子在一起是她工作中最棒的部分。 In his opinion,to be with children is the best part of this activity.(具体) 在他看来,与孩子们在一起是这项活动的最佳部分。 2.动名词作主语时,通常用来表示一件已知的事或经验;动词不定式通常用来表示一件未完成的事或目的。 It is widely known that ... ...