it is adj.of sb.to do sth.it is adj.from sb.to do sth.

某人做某事是很.的
It is wise of you to leave him.
你离开他是很明智的.
没有it is adj.from sb.to do sth.只有 it is adj.for sb.to do sth.
It is hard for you to leave him.
你离开他是很困难的（事情）
注意两个句型的区别哦