It's clever for him to work out the difficult math problem.单句改错
问题描述：
It's clever for him to work out the difficult math problem.单句改错
答
it's +adj +for/of sb to do sth
当形容词是指人的品质方面的,如bad坏,kind,distingue高尚的等等,则应该用of
其他情况下一般用for.
所以此句应把for改为of