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。