Unit 4 Grammar——it用作形式主语（教用Word）-【勤径学升】2024-2025学年高中英语选择性必修2同步练测（外研版2019）

Grammar——it用作形式主语[对应学生用书第72页] 用it用作形式主语完成下面教材中的句子并体会它们的语法特征 1．(教材P50)But it is vital not to take any chances. 2．(教材P50)When I saw the tragic scenes on the news, I felt it was my duty as a doctor to go there and offer my help. 3．(教材P50)It is important to remember that Ebola doesn't respect national boundaries. 4．(教材P52)It is so inspiring to have colleagues like Wilton, Maisy and Alfonso, not to mention all the others I have worked with. 5．(教材P52)In a world still facing so many problems, it is absolutely essential for us all to collaborate to create a global community with a shared future of peace and prosperity. 当动词不定式、动词­ing形式或从句作主语时，通常把它们置于句末，而用it作形式主语，放在句首。 要点一　it代替不定式作形式主语 不定式(短语)作主语时往往主语太长，句子结构不平衡，此时可用it作形式主语，把不定式(短语)放在句末。常用于下列句型中： 1．It＋is/was＋adj./n.＋to do sth.(不定式前可有其逻辑主语for/of sb．) It is difficult for the elderly specialists to find the cure for the disease in such a short time. 对于这些年迈的专家来说，在如此短的时间找到疾病的治愈方法太难了。 It's very kind of you to help me. 你帮助我真好。 It is everyone's duty to obey the law. 遵守法律是每个人的义务。 [名师点津] (1)当作表语的形容词(easy、hard、difficult、important等)说明不定式行为的性质和特点时，常用“for sb．”引出不定式的逻辑主语。 (2)当作表语的形容词(kind、nice、good等)说明不定式的逻辑主语的性格和品行时， 常用“of sb．”引出不定式的逻辑主语。 2．It takes sb．some time to do sth. It took us three years to tackle the project. 我们花费三年时间才处理了这项工程。 3．It's up to sb．to do sth. It is up to us to help those in need． 帮助那些有困难的人是我们的责任。 [对点训练1] 语法填空 ①It is not up to you to tell(tell)me how to do my job． ②It is not right to use(use)these places as rubbish dumps. ③It was very thoughtful of her to come to see me when I was ill. 要点二　it代替动词­ing形式作主语 有些句型中it作形式主语，真正主语为动词­ing形式： 1．It's useless/(of)no use/(of)no good doing sth.做……是徒然的/没有用的/没有益处的。 It is no use giving him some advice. ＝It is useless giving him some advice. 给他提建议没用。 2．It is a waste of…doing sth.做某事是浪费……的。 It is a waste of time watching TV. 看电视是浪费时间的。 [对点训练2] 完成句子 ①It is a waste of time trying to persuade him to change his mind． 试图说服他改变主意是在浪费时间。 ②It is no use talking to him about it． 和他谈这事没有用。 要点三　it代替从句作主语 用it作形式主语代替从句的结构主要用于下列句型： 1．It be＋adj.＋that…(常用于此句型的形容词有：certain、doubtful、important、necessary、easy、strange、national等) It is certain that free medical care will be given to most people in our city. 我们城市的大多数人将享受免费医疗，这是肯定的。 2．It be＋n.＋that…做……是……的(常用于此句型的名词有：pity、honour、shame、wonder等) It's a pity that I didn't think of it earlier. 我没有早一点这么想真是遗憾。 3．It be＋过去分词＋that…据……(常用于本句型的过去分词有：said、announced、believed、reported、known、hoped等) It is reported that more than twenty people were killed in that bus accident. 据报道在那次的公共汽车事故中有二十多人丧生。 4．It happens/turns(ed)out/occurred to sb．that…碰巧/结果是/某人突然想起…… It occurred to her that she might adopt a homeless child． 她突然想到她可以收养一个无家可归的孩子。 [对点训练3] 语法填空 ①It is hoped(hope)that the number of deer will greatly increase very soon. ②It suddenly occurred to me that I knew how to solve that problem. ③It is strange that he should have left without telling us. Ⅰ.单句语法填空 1．It's no good taking(take)over the experience of foreign countries uncritically. 2．It's kind of you to help me with the problem. 3．It is known(know)to us that he is one of the most famous football players in the world． 4．It's no use complaining(complain)that you don't have an opportunity to get an ideal job． 5．It never occurred to me that you could succeed in persuading him to change his mind． 6．It is very kind of you to assist(assist)me to clean the dusty shelf. 7．It is known that he is one of the best teachers in our school. 8．It is difficult to figure out a global population of polar bears as much of the range has been poorly studied． 9．It is requested that he (should)give(give)a performance at the party. 10．It is necessary for us to master a foreign language. Ⅱ.句型转换 1．We all knew that they had broken their promise. →It is known that they had broken their promise. 2．To master a foreign language without much memory work is impossible. →It is impossible to master a foreign language without much memory work. 3．That you have forgotten both her address and her telephone number is a pity. →It is a pity that you have forgotten both her address and her telephone number. 4．To get to my school from my home by bike takes me half an hour. →It takes me half an hour to get to my school from my home by bike. 5．Don't you think trying to get Betty to change her mind is a waste of time? →Don't you think it is a waste of time trying to get Betty to change her mind？ 学科网（北京）股份有限公司 $$