把It is clever of you to solve this problem.改成由that引导的主语从句怎么做啊?

题目

把It is clever of you to solve this problem.改成由that引导的主语从句怎么做啊?
还有这两句也是改成由that引导的主语从句：1.It is foolish of him to go alone.2.It is difficult for us to master a foreign language.

答案

It is clever of you to solve this problem.
===it is very clever of you that you solve this problem
=== That you solve this problem is very clever of you .
1.It is foolish of him to go alone.=== that he goes alone is foolish
2.It is difficult for us to master a foreign language.===that we master a foreign language is difficult.