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课件网) Unit 5 Working the Land Grammar: 主语从句 一、概念 在主从复合句中，充当主语的从句叫主语从句，它是名词性从句之一。名词性从句分为：主语从句，宾语从句，表语从句和同位语从句。 二、连接词 引导主语从句的连接词有： ① 从属连词：在从句中不作成分 (that; whether/if) ② 连接代词：在从句中作主语、宾语、表语或定语 (who,whom, whose, what, which, whoever, whatever, whichever等) ③ 连接副词：在从句中作状语 (when, where, why, how) (1) 从属连词：that, whether/ if ① that在从句中不充当句子成分，也无意义，只起连接作用，但不可省略。 That smoking is harmful to health is known to everyone. 吸烟有害健康，这是大家都知道的。 That you don’t like him is none of my business. 你不喜欢他不关我的事。 That the college will take in more new students this year is true. 今年这所大学将招收更多新生是真的。 (1) 从属连词：that, whether/ if ② whether/if在从句中不充当句子成分，只起连接作用，意为“是否”。whether引导的主语从句既可放在句首，也可放在句末。而if引导的主语从句不能放在句首，只能放在句末。 Whether life exists on other planets is not clear yet. It is still doubtful whether/ if she will react quickly to our suggestion. (2) 连接代词： 连接代词包括 who, whom, whose, what, which, whoever,whatever, whichever等 连接代词引导主语从句时，在句中既起连接作用，又在从句中充当主语、宾语、表语或定语。 Who will demonstrate new educational software hasn’t been decided yet. Whoever solves the puzzle can receive the award. (3) 连接副词：when, where, why, how when, where, why, how在从句中作状语，分别表示时间、地点、原因和方式。 When we will set off hasn’t been decided. 我们将何时出发还没有决定。 Why he used that gesture puzzled me for a long time. 他为什么使用那个手势困扰了我很长时间。 三、用it作形式主语，主语从句后置的句型 当主语从句太长，为了避免头重脚轻，常用it作形式主语，而把主语从句后置。 用it作形式主语的常见句型有： (1) It+ be+形容词+ that从句。 该句型常见形容词有clear, obvious, true, natural,possible, likely, certain, fortunate, strange, necessary,important等。 【例句】It is clear that charges vary according to size. 三、 用it作形式主语，主语从句后置的句型 (2) It+ be+名词（词组）+ that从句。 该句型常见的名词（词组）有a pity, a shame, good news,a fact, an honour,a wonder, no wonder等。 It is a pity that your parents didn’t permit you to go with us. It is no wonder that you’ve achieved such great success. 三、 用it作形式主语，主语从句后置的句型 (3) It+ be+过去分词+ that从句。 该句型常见的过去分词有said, believed, reported,thought, expected, decided, announced, suggested, hoped等。 It is reported that a violent earthquake happened in Wenchuan, China. It is believed that boys were better at science than girls. 【误区警示】 当过去分词是suggested, ordered, required, advised, requested,insisted等表示建议、要求、命令等的词时，主语从句应使用虚拟语气，即谓语动词用“(should+)动词原形”。 It is suggested that the work (should) be done with great care. 有人建议，这项工作应该特别谨慎地去做。 It is suggested that you （should） spend mor ... ...
