It is/was + 形容词 + for sb. to do

It is/was + 形容词 + for sb. to do

It is/was + 形容词 + for sb. to do.../做某事对某人来说……

It是形式主语，真正的主语是不定式to do sth。例如：

It's not easy for us to study English well.

对我们来说学好英语并不容易。

It's a good idea for us to travel around the world.

周游世界对我们来说是个好主意。