问题
单项选择题
关于对散射线的叙述，错误的是
A．kV升高散射线含有率加大
B．原发射线能量越大散射角越大
C．散射线光子能量随kV升高而增加
D．原发射线能量越大照片灰雾越大
E．80～90kV以上时散射线含有率趋向平稳
答案
参考答案：B
解析：原发射线能量越大散射角越小。
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关于对散射线的叙述，错误的是
A．kV升高散射线含有率加大
B．原发射线能量越大散射角越大
C．散射线光子能量随kV升高而增加
D．原发射线能量越大照片灰雾越大
E．80～90kV以上时散射线含有率趋向平稳
参考答案：B
解析：原发射线能量越大散射角越小。
It was black in the evening. Jason, a 12-year-old boy didn’t want to go outside. But his mother, Branda, was worried about his father and 36 he go. That evening the man had to 37 his car, a Buick outside their house in the driveway. 38 enough, the wife hadn’t heard a single 39 for at least one hour. “Go and find him,” she told Jason. The kid stepped outside in the darkness and called into the shadows “Dad?” “Jason?” 40 was his father, but his voice sounded 41 . He spoke slowly, in a strange way. That evening, when the man had to get 42 the car to fix it, he used a forklift to lift the car. 43 , the man didn’t place the blocks in front of the car’ s front tires to keep it from 44 forward off the forks, which was exactly 45 it did afterwards. Little Jason saw his dad’s feet 46 out from beneath the car. 47 to take a full breath, Old Jason sank into a sleepy, half-alive 48 . “Calm down. It will be OK.” The boy 49 his mother. Now he couldn’t afford to be scared. He climbed on and started up, the Buick started to come off the ground and 50 in the air. Minutes later, 911 policemen arrived. Old Jason 51 beneath the car, still breathing. It wasn’t 52 his dad was loaded into an ambulance that the little boy 53 and sobbed. Little Jason says one happy change has come out of the 54 : he gets to spend more time with his dad. Old Jason, who hasn’t touched a car 55 the Buick fell on him often spends evenings with his son playing.
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