Question

it is difficult for sb to 和 make sb hard to do sth 有什么区别？

Answer 1

若形容词是描述不定式行为者的性格、品质的，如kind，good，nice，right，wrong，clever，careless，polite，foolish等，用of sb.。

It’s very kind of you to help me. 你能帮我，真好。

It’s clever of you to work out the maths problem.
你真聪明，解出了这道数学题。

若形容词仅仅是描述事物，不是对不定式行为者的品格进行评价，用for sb.，这类形容词有difficult，easy，hard，important，dangerous，（im）possible等。

It’s very dangerous for children to cross the busy street.
对孩子们来说，穿过繁忙的街道很危险。

It’s difficult for us to finish the work. 对我们来说，完成这项工作很困难。

注 意 ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

of sb. 的句型通常都可转换为不定式作状语的句子，但for sb. 句型不可以。

It’s very nice of you to offer me a seat.

= You are nice to offer me a seat. 十分感谢你给我让座。

It is careless of him to lose so many things.

= He is careless to lose so many things. 他丢了这么多东西，真是太粗心了。

It’s very important for you to practise your oral English in daily life.
在日常生活中练习你的英语口语非常重要的。

这句话不能说成：It is very important of you to practise…

Answer 2

前一个短语的意思是：（事）对于某人来说很困难。主语侧重事情。后一个短语的意思是：让某人很难地做某事，侧重于人的主观。

Answer 3

1 对某人来说很难。“让他说出事实很难”it is difficult for he to tell the story.
2 让某人难以做某事。“我们让他不能说出事实”we make him hard to tell the story.