'You want to be more careful,' said Snape. 'Hanging around like this, people will think you're up to… — J.K. Rowling

'You want to be more careful,' said Snape. 'Hanging around like this, people will think you're up to something. And Gryffindor really can't afford to lose any more points, can they? … Be warned, Potter — any more night-time wanderings and I will personally make sure you are expelled. Good day to you.'

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