最简单的：Nobody / no one can answer the question.
其他：（There's）Nobody / no one knows the answer to the question.
There isn't a single person knows the answer to the question.
None of the people knows the answer to the question.
Hardly do people know the answer to the question.
Nobody / no one has any idea to answer the question.
希望我的回答对你有帮助,谢谢.
