Panic does not help, even if you are unable to answer. Try to ask questions to the interviewers as well and it should be impressive enough.

We ask questions, and they don't answer.

There are years that ask questions and years that answer.

You should not ask questions without knowledge.

A wise man can be a fool in love.

I myself don't know what makes my books work. I enter a bookstore and I'm frankly overwhelmed by the number of books in most of them, and I know people are buying mine.