他一定在打篮球，他不可能正在打篮球。用英文怎么说

HE must be playing basketball…………
it's impossible!!!
满意了么……

He must be playing basketball, but in fact he couldn't be.

这句话本身有毛病，一定在打篮球这个打篮球是他职业是打篮球，还是正在打？或者还是什么东西！

He must be a basketball player,but he can not be playing basketball.