为保持句子平衡，用it来代替动词不定式，在句子中作形式主语或形式宾语。如：

Question

如题所述

Answer 1

It is important to study English well.追答

to study English well 作主语。

I think it important to study English well.
it 形式宾语，to study English well 真正宾语

谢谢好评

本回答被提问者采纳

Answer 2

Let's take a vacation soon.

Answer 3

It’s nice not to depend on them . 不依靠他们是好的。
It ’s hard to restore a brokenmirror .破镜难圆。
It’s a shame to say like that .那样说话是可耻的。
It’s silly to believe him . 相信他是愚蠢的。
It isn’t hard for one to do a bit of good . 一个人做点好事并不难。
It will be a mistake for us not tohelp them . 对于我们来讲，不帮助他们是个错误。
It’s not easy for him to admit hismistakes . 对他来说承认错误是不容易的。
It’s a proper choice for me tostudy English . 对我来说学习英语是恰当的选择。
It’s impossible for him to find agood job . 对他来说找到一份好工作是不可能的。
They found it impossible to geteverything ready in time .
他们发现不可能把一切按时准备好。　
She thought it unnecessary to arguewith him about it .　她觉得没必要和他辩论。
I consider it better not to go . 我认为还是不去为好。
I find it interesting to studyEnglish . 我发现学英语很有趣。

Answer 4

如:追答

It is important to learn English well.

It 作形式主语

I find it hard to learn English well.

it 作形式宾语