it's very nice of you=It's very kind of you=That's very nice of you
这三句在口语中用的比较多，意思是“你真好”。
以下是三种语境：
It is very nice of you to invite us.
你邀请我们,真是太好了.
2.It is very nice of you to be so considerate.
你们想得这样周到是很好的.
3.It is very nice of you to come to see me.
你来看我太谢谢了.
这个句型的原型是：It is＋形容词＋for （ of） sb.to do sth.句型。
当形容词是kind ,nice ,good ,clever ,careful ,careless ,right ,wrong ,foolish 等表示人的性格特征时,用of ;形容词为difficult ,easy ,hard,important ,interesting,possible ,necessary 等表示事物的特征时,用for。
如：It is necessary / important / easy / hard/ possible for us to learn English well.用of的形容词强调人的品格或者性格，用for的形容词强调事情的属性。