5. You ... smoke on the plane – it's against a) Shouldn't b) Can't c) May not d) Mustn't 6. I can do it myself. You ... bother. a) Mustn't b) Shouldn't c) Needn't d) Wouldn't 7. You ... be so friendly to every person yo Needn't b) Shouldn't c) Mustn't d) Can't 8. Someone's at the door. It ... be Sharon, come.