期末复习语法突破讲练-动词不定式作主语和表语讲义-2023-2024学年高中英语译林版（2020）选择性必修第三册

动词不定式作主语和表语 1．动词不定式的时态和语态 语态 时态 主动 被动 一般式 to do to be done 进行式 to be doing 完成式 to have done to have been done 2.动词不定式作主语 动词不定式作主语时，一般表示具体的或一次性的动作。作主语的不定式有时态和语态的变化，且谓语动词通常用单数。 To finish this job in one day is impossible. 要在一天之内完成这项工作是不可能的。(表示具体的情况) 动词不定式作主语时，有以下两种形式： (1)把不定式置于句首 ❶To 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。 (2)用it作形式主语，把作真正主语的不定式(短语)后置，常用于以下结构中： ①It ＋be＋名词＋to do sth. ❷It's our duty to take good care of the old. 照顾好老人是我们的责任。 ②It takes sb.＋some time＋to do sth. ❸How long did it take you to finish the work? 你花了多长时间来完成这项工作？ ③It＋be＋形容词＋for sb.＋to do sth. ❹It is difficult for us to finish writing the composition in a quarter of an hour. 在十五分钟内完成这个作文对我们来说太难了。 ④It＋be＋形容词＋of sb.＋to do sth. ❺It 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一种很笨的方法。 [特别注意]　动名词(短语)作主语多表示一般性的、抽象的、重复性的动作或状态。 Reading poems gives me much pleasure. 读诗给我带来很多乐趣。 3．动词不定式作表语 动词不定式(短语)作表语通常用来说明主语的具体内容(职业、职责或性质等)，也可以表示目的、愿望等。 ❶A college counsellor's job is to help students adjust to college life. 大学辅导员的工作是帮助学生适应大学生活。 ❷His ambition is to become an actor. 他的理想是成为一名演员。 [特别注意]　①常见的后接动词不定式(短语)作表语的系动词有appear，seem，prove，remain等。 ❸Our English teacher seems to have known the secret. 我们的英语老师好像已经知道这个秘密了。 ❹Whether we will succeed or not remains to be seen. 我们是否会成功仍待观察。 ②当主语部分含有实义动词do的某种形式时，不定式(短语)作表语时通常省略to。 ❺All I can do now is keep silent.我现在所能做的就是保持沉默。 练习 Ⅰ.用括号内适当形式填空 1．____________ (see) is to believe.I won't believe it until I see it by myself. 2．As a student in senior high school，the most important task is ____________ (study) hard，which determines your future. 3．Exercise energizes you，so it is more difficult ____________ (relax) and have a peaceful sleep when you are very excited. 4．His plan is ____________ (buy) a new computer for his son as a reward for his good behavior at school. 5．What squirrels can do is ____________ (store) all kinds of nuts before winter comes. 6．It took him a long time ____________ (recover) from a