题目

阅读短文并回答问题。    One weekend , a wife and a husband（丈夫）went to visit a shop in Tokyo. After they got back home ,they couldn’t find their camera(照相机).They thought the camera must be in the shop . After a few weeks , they went to that shop again and the boss of the shop gave their camera back to them.    When their pictures of the camera came out ,the husband saw two pictures he did not take . One is a man standing at the door of the shop .In his hand there is a piece of paper（纸） with some words on it “I find your camera .” The other is a boy下列实验装置图所示的实验操作，不能达到相应的实验目的的是