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问题 单项选择题

关于原射线的叙述，不正确的是（）

A、指从放射源（或X射线靶）射出的原始X（γ）光子

B、它的剂量等于总吸收剂量与散射剂量之差

C、有效原射线剂量包括原射线与准直系统相互作用产生的散射线光子

D、有效原射线剂量不包括原射线与准直系统相互作用产生的散射线光子

E、它在模体中任意一点的注量遵从平方反比定律和指数衰减定律

答案

参考答案：D

完形填空

根据短文内容和汉语提示，用所给词的正确形式填空。每空限填一词。（10分）

The study of English in Grade Three is really interesting although it is a    小题1:      

(艰苦的) task for most of us to learn it well. Yes, not easy. In the last few weeks, we have learned about the  小题2: (自然的) wonders of the world, the adventures of Tom Sawyer, Liu Xiang and the great  小题3: （发明） of paper and printing. When you stand on the edge of the Grand Canyon, you can feel the ground fall away and down to a river, far    小题4:  （在下面） you. How great it is! Mr Jackson’s favourite   小题5:  （场景） of the book by Mark Twain is that people are  小题6:   （高兴） to see Tom 小题7: （活着的）. Liu Xiang’s story tells us to work hard so that we can  小题8: （打败）the difficulties by ourselves. We also learned that people are thinking about if paper will be  小题9:  （替代）by computers. However, looking 小题10:（浏览）a magazine at hand is easier than turning on a computer. Don’t you think so?
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单项选择题

定点符号法中，分别用符号的（）表示物体的质量特征和数量差别。

A.形状和大小

B.灰度和大小

C.颜色和灰度

D.形状和灰度
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