1. B: 'No, it can't be. The original is in a museum in Paris.'
2. B: 'I may come. I haven't decided yet.'
3. B: 'It must be. That artist only worked with oil.'
4. B: 'They must have. Renoir painted a portrait of Monet in 1875.'
5. B: 'I’m not sure, I think it must be a man.'