中小学教育资源及组卷应用平台 Unit 4 It作形式主语及难点分析 it 作形式主语 英语中为了保持句子结构平衡,避免句子头重脚轻,经常用it作形式主语代替句子中较为繁琐的真正主语,it没有实际意义。用it作形式主语的情况有以下三种: 一．it 代替 to do... 作形式主语 在很多情况下，人们通常用it作为形式上的主语，而把不定式移到谓语之后,使句子结构显得平衡一些。 >(1)it+be+adj.+(of sb.+) to do... It's impolite to turn your back to your teacher and refuse to answer. 背对着老师,拒绝回答问题是不礼貌的。 It is impossible to learn a foreign language without making painstaking effort. 想不下苦功夫就学会一门外语是不可能的。 【温馨提示】当主语和表语都是不定式时,不能用形式主语it代替不定式。 To respect others is to be respected.尊重别人就是尊重自己。 To become a slave is to give up one’s freedom做奴隶就等于放弃自由。 >(2)it+be/seems等+名词(词组)+to do... It seemed a pity to have wasted so much time. 浪费了这么多时间，真是遗憾。 it+be+介词短语+to do.... It is against my principle to do it.做此事违背了我的原则。 (4)it+及物动词+宾语+to do... It took us determination and perseverance to finish the tough task. 完成这项艰难的任务需要我们的意志力和恒心。 二．it 代替动名词(短语)作形式主语 (1)it+be+n.+doing…(名词多为a waste of..., no use, no good,fun 等) It's no use arguing with such a stubborn man. 与这样一个固执的人争论是没用的。 (2)it +be+adj.+doing.(形容词多为useless, worthwhile,pleasant等) It is pleasant working with a responsible person. 与一个负责任的人共事是很愉快的。 三.it 代替从句作形式主语 >(1)it is+名词(词组)+从句(常见的名词词组有an honour, a pity, a shame, a surprise, a fact, common sense/knowledge) It is a pity that in the story nobody helped the wounded. 很遗憾，在故事中没有人帮助受伤者。 It is common knowledge that the United States is one of the biggest developed countries in the world. 美国是世界上最大的发达国家之一,这是常识。 (2)it is +adj.+从句(常见的形容词有natural,true, strange, funny, important, necessary, right, clear, obvious, certain, surprising, wonderful, possible, likely,probable 等) It is certain that free medical care will be given to most citizens. 大多数市民将享受免费医疗,这是肯定的。 It is not surprising that such worms can break down polyethylene. 这种蠕虫可以分解聚乙烯并不奇怪。 【温隆提示】1t’s important/necessary/right/strange /natural..that.. ( should) do... (3)it+动词(短语)+从句[常见的动词(短语)有seem, turn out, happen,look, appear, matter, strike,occur 等] It turns out that just looking at green, growing things can reduce stress, lower blood pressure,and put people into a better mood. 事实证明,只看绿色、正在生长的东西能减轻压力,降低血压,并且使人们心情更好。 【温馨提示】It doesn't matter whether/if.. It looks/seems as if.. it+be+过去分词+从句(常见的过去分词有 said,reported,believed,recognized,known, decided, proved, thought, expected,announced,arranged 等) It is recognized that the government should play an important part in wildlife protection. 人们公认,在野生动物保护方面政府应该起重要作用。 难点一： 过去分词短语作后置定语 教材例句 It is an independen ... ...
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