用焦距不变的照相机给某个同学拍完全身像后，想再拍一张半身像，则照相机应 该同学，同时镜头离底片 一些（均填“靠近”或“远离”）。
靠近 远离
题目分析：照相机是凸透镜的应用，把物体放在二倍，焦距之外，成倒立缩小的实像；根据物远像近像变大的原理，给某个同学拍完全身像后，想再拍一张半身像，需要她的像变大，所以物距减小，像距变大，所以照相机应该靠近该同学，同时镜头与底片远离一些。
点评：焦距本题的而关键是熟知物远像近像变大的含义。
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| One summer in college, I was invited to be an instructor at a high school leadership camp. I first 1 a boy under the tree on the first day of camp. His obvious 2 and shyness made him appear weak and lonely. Nearby, 200 3 campers were playing and joking, but the boy seemed to want to be anywhere 4 where he was. I was instructed to care more about campers who might feel 5 . So I 6 him and said, "Hi, I'm Kevin. It's nice to meet you. How are you?" 7 a shaky voice he 8 answered, "Okay, I guess." I calmly asked him to join in the activities and 9 some new people. He quietly replied, "No, this is not really my thing." I could 10 that this whole experience was 11 to him. But I somehow knew it wouldn't be right to 12 him, either. It was going to take more time and 13 . The next day, I was leading camp songs for the campers. They eagerly participated. But the boy was just sitting alone, 14 out the window. That evening at our nightly staff meeting, I made my 50 about him known. I asked them to pay special attention and spend time with him 51 they could. The days flew by fast. When the "last dance" came, surprisingly, the boy from under the tree was now a shirtless dancing 52 . He owned the dance floor 53 meaningful time with others. I couldn't' believe it was him. In that instant, I realized how easy it is to give a bit of 54 every day. You may never know how much each gesture may mean to someone else. I tell this story as 55 as I can, and I advise others to look out for their own "boy under the tree." | ||||
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