这个形式一般用于形容人的性格,对象一般是人.比如：It's kind of you to help me.这种形式可改写为：You are kind to help me.
adj.+for+n.+to do 则范围较大,可以是人,可以是物,比如：It's easy for me to solve the problem.这种句式怎么不能改成上一种句式,只能改成：To solve the problem is easy for me.