Sometimes somebody asks you a question and you don't know the answer. Here are some phrases that you can use when you don't know.

Sorry. I don't know.
(I'm afraid,) I've no idea.
(Sorry,) I can't help you there.
I don't know anything about...
I don't know the first thing about...
I haven't got a clue.
Search me.
Don't ask me.
What are you asking me for?
How the hell should I know?

Explanations

• In phrases 1, 2 and 3 we can use either "Sorry" or "I'm afraid" or we can leave this part of the phrase out. These phrases are quite polite.
• Phrases 4 and 5 are saying that you don't know the answer and that you don't know about the whole topic area.
• Phrases 6 and 7 are saying (more strongly) that you don't know anything about the topic.
• If you say phrases 8 or 9, you are probably a little angry that somebody asked you a question about this topic.
• Phrase 10 is showing stronger annoyance that somebody asked you about a certain topic.