He never finished what he was going to say for at thatmoment something happened. The high.backed chair infront of the fire moved suddenly and there rose up out ofit.like a pantomime demon coming up out of a trapdoor. the alarming form of Uncle Andrew. They were not in the empty house at all； they were in Digory‘s house and in the forbidden study！ Both children said “O.o.oh” and realized their terrible mistake. They felt they ought to have known all along that they hadn’t gone nearly far enough.
Uncle Andrew was tall and very thin. He had a long clean. shaven face with a sharply pointed nose and extremely bright eyes and a great tousled mop of grey hair.
Digory was quite speechless， for Uncle Andrew looked a thousand times more alarming than he had ever looked before. Polly was not so frightened yet； but she soon was. For the very first thing Uncle Andrew did was to walk across to the door of the room， shut it， and turn the key in the lock. Then he turned round， fixed the children with his bright eyes， and smiled， showing all his teeth.
“There！” he said. “Now my fool of a sister can‘t get at you！”