It's no use to boast of anything until it's done, nor then, either, for it speaks for itself.

凡事八字未见一撇，不可吹嘘张扬。谨慎从事，低调做人，事实胜于雄辩。

Harry was sure that Dumbledore was going to refuse, that he would tell Riddle there would be plenty of time for practical demonstrations at Hogwarts, that they were currently in a building full of Muggles and must therefore be cautious.

哈利以为邓布利多一定会拒绝，他以为邓布利多会对里德尔说，以后在霍格沃茨有的是时间做具体示范，并说他们眼下是在一座住满麻瓜的楼房里，必须谨慎从事。