问题
单项选择题
关于利用磁偏转展宽电子束的特点，下列描述哪项错误（）？
A.能谱窄
B.剂量跌落更陡峭
C.较低的X线污染
D.采用类似电视光栅式扫描或螺旋式扫描的方法
E.易形成电子束不规则调强射野
答案
参考答案：E
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关于利用磁偏转展宽电子束的特点，下列描述哪项错误（）？
A.能谱窄
B.剂量跌落更陡峭
C.较低的X线污染
D.采用类似电视光栅式扫描或螺旋式扫描的方法
E.易形成电子束不规则调强射野
参考答案：E
A woman is going shopping. She is going boat. The boat is going across（穿过）the river. Her basket is empty（空的）. Oh dear! Look! Her basket is in the .“Help!”she says.“Look! My basket is in the river.” A boy sees the basket. He says, “Don’t worry! I can it! I’m a very good swimmer.” He takes _ _his shoes and shirt. “Look my shirt and shoes, please!” he says and then jumps _____ the river. A sees the basket. “I can go by basket!” it thinks. It gets to the basket. The boy in the river. “Where’s the basket?” he calls:“It’s ____ there!” calls the woman. “It’s behind you!” It’s that duck! The boy gets to the basket.“Go away!” he says __ __ the duck. The duck out of the basket and swims away. The boy takes the basket to the land. “Oh, thank you!” says the woman. “Thank you very much!” “Not at ___ __!” says the boy.“ you like to give me my shirt and shoes?” “Yes, here you are. Oh, what’s in the basket? It’s the duck’s .”
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