What do you say when…

…your mind wanders and you didn’t really hear what somebody said to you. If you were thinking of something else, you were dreaming or day-dreaming.
Last night I was with a group of friends and this happened to me. We were watching a DVD and then having a discussion about the content. Someone was talking and I suddenly realized that my mind had drifted on to something completely different and I had missed what had been said. Then someone asked me a specific question about it!
If you want to be honest, you can admit that you haven’t a clue what they’d been talking about. “Sorry, I was away with the fairies!” is one way of saying this. It means you weren’t paying attention.
Of course, you could hedge a bit and say something vague like “D’you think you could just run over that again? I got the general gist, but I missed the last bit. What exactly were we talking about?” If you’re lucky, someone will fill you in.
If you were listening and you actually didn’t understand something, you might say ‘Come again?’ That just means “Could you say it again please?’ Or you could admit that you didn’t understand. “Sorry, I lost the plot there for a while. Can we start again?”

My mind wandered
My mind drifted (Careful: 'I drifted off' usually means go to sleep)
I haven’t a clue or I haven't got a clue
I was away with the fairies
I got the general gist
Can you fill me in- give you the details
I'll just run over it again - explain it once more
Come again?
I lost the plot (can also mean to be crazy OR to get really angry)

Go to souNZ English to hear the above.