Rewrite the sentences so that the second sentence has the same meaning as the first. Use must, could or can't. I'm sure that's John over there. That must be John over there. Our teacher is late today – maybe she's ill. She ill. I don't think that's Phoebe's brother. He doesn't look like her. That Phoebe's brother. I'm sure that isn't Henry. He's in Australia. Henry. I'm sure Sarah has my book. I saw it on her That desk. Sarah my book. His mum says he's in bed. Perhaps it's true. in bed.