需要注意的是，作为形式主语的it并无实际意义，只是为了满足语法上的需要，避免句子头重脚轻，它代替的是句子的逻辑主语，而真正主语由从句或不定式充当。形式主语一直都是高频考点，还请大家多多练习。
与汉语习惯不同，英语习惯将较重要的信息放在句子后半段，为避免头重脚轻，就产生了一个逻辑主语it，同时也就产生了一种新的的语法现象——形式主语。今天小编整理了一些由名词性从句作真正主语的情况，一起来看一下吧。
It +动词+从句
seem,appear,happen,look,matter,make,strike,occur
It appeared that he had a happy childhood.
看来他有一段幸福的童年。
It made us very happy that she was saved.
她能化险为夷令我们大家很高兴。
It is +形容词+从句
true,strange,necessary,important,certain,wonderful,possible,likely,probable
It is certain that free medical care will be given to most people in our city. 我们城市的多数人将享受免费医疗，这是一定的。
It is obvious that he has been treated.
很明显他已经被款待了。
It is +名词+从句
fact,surprise,pity,honor,common knowledge
It is common knowledge that the moon cannot give out light. 月亮不会发光，这是常识。
It is a surprise that you gave such an answer to the question. 你对这个问题作了这样的回答，令人吃惊。
It+be+分词+从句
said,reported,believed,known,decided,thought,expected,announced
It is said that Jack has been to Europe.
据说Jack去过欧洲。
It was reported that a new park will be built.
据报道将要建造一个新的公园。
需要注意的是，作为形式主语的it并无实际意义，只是为了满足语法上的需要，避免句子头重脚轻，它代替的是句子的逻辑主语，而真正主语由从句或不定式充当。形式主语一直都是高频考点，还请大家多多练习。
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