A:Where were you last night, at exactly nine twenty PM?
B:nine twenty pm,I couldn't say.I cann't remember.
A:Are you sure you cann't remember?
B:I've absolutely certain.
A:Were you in or out?Can you remember that?
B:I'm not quite positive.I think I went out at about half pass nine.
A:Did you see anyone come into the block flats?
B:No, I didn't.
A:Sure?
B:Quite sure.