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问题 选择题

用显微镜观察小鱼尾鳍血液流动时，视野很暗，影响观察，此时应采取的措施是[ ]

A．调节准焦螺旋

B．缩小光圈

C．把平面镜换用凹面镜反光

D．把低倍物镜换用高倍物镜观察

答案

答案：C

单项选择题

A young man was going to join the army (军队) and had to (41) a medical examination. The doctor was sitting at a desk when he came in. He said to the man, "Take your coat and shirt off and (42) on that chair.
The young man did so. The doctor looked at him for a moment without (43) up from his chair and then said, "All right. Put your clothes on again.
"But you haven’t examined me at ail!" the young man said in (44) .
"There is no need to do so," the doctor said with a (45) .
"When I (46) you to take your coat and shirt off, you heard me all right, so there is nothing wrong with your (47) . You saw the chair, so your eyes are (48) . You could take your clothes off and sit on the chair, so you must be in good health. And you understand what I told you to do and did it without a (49) , so you (50) healthy enough for the army.\

[A] pity[B] smile[C] pleasure
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判断题

个体乳酸阈强度是发展有氧耐力训练的最佳强度。( )
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