ect: Hi I (1) must / should have been mad to enter the karaoke competition last night. What was I thinking? I really (2) can’t / should have thought about it a bit more carefully. Why did I agree to it when I (3) could / would have stayed at home and watched a DVD instead? But no I made a complete fool of myself in front of all my friends. It might (4) be / have been all right if they'd given me a song I knew. But it was this really weird song I'd never heard before. I (5) can’t / mustn't have got any of the notes right. It was so embarrassing ​