显微镜的镜头脏了，要用（ ）擦拭干净．
A．擦镜纸
B．纱布
C．纸巾
D．作业纸
清洁镜身时应有纱布；清洁物镜和目镜的镜头时，应用擦镜纸．擦镜纸质软又不易掉毛，用擦镜纸擦拭镜头既可以清洁镜头，又可以避免损伤镜头和有少量的纤维留在镜头上，影响观察效果．通过分析知道当显微镜镜头不清洁时，除去污物，是对显微镜的物镜和目镜的镜头能进行清洁，所以应用擦镜纸擦拭．
故选：A．
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| When I was in the seventh grade, I was a candy striper(义I) at a local hospital in my town. I 1 about thirty to forty hours a week during the summer. Most of the time I spent there 2 with Mr Cillespie. He never had any 3 , and nobody seemed to care about his 4 . I spent many days there _ 5 his hand and talking to him, helping with 6 that needed to be done. He became a close friend of mine, 7 he responded with only an occasional 8 of my hand. Mr Gillespie was m a coma(昏迷). I left for a week to 9 with my parents, and when I came back, Mr Gillespie was gone. I didn't have the 10 to ask any of the nurses where he was, 11 fear they might tell me he had died. So with many 12 unanswered, I continued to volunteer there through my eighth-grade year. 13 years later, when I was a junior in high school, I was at the gas station when I noticed a 14 face. When I realized who it was, my eyes were filled with tears. He was 15 ! I asked if he was Mr Gillespie. With an 16 look on his face, he replied yes. I explained how I knew him and that I had spent many hours talking with him in the hospital. Tears 17 up in his eyes, and he gave me the warmest bug I had ever 18 . Then he told me about his life and what 19 of him to put him in the coma. We cried for a while and exchanged a bug, said our goodbyes and went our 20 ways. | ||||
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