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问题 单项选择题

关于准直器作用的描述，不正确的是

A．减少受检者X线辐射的剂量
B．对X线的宽度进行调节，从而决定扫描层厚
C．减少散射线的干扰
D．限制焦点几何投影所致的半影作用，提高图像质量
E．吸收低能射线，优化射线的能谱

答案

参考答案：E

解析： 吸收低能射线，优化射线的能谱是滤过器的作用。

改错题

短文改错。
     此题要求改正所给短文中的错误。对标有题号的每一行做出判断：
     如有错误（每行只有一个错误），则按下列情况改正：
     此行多一个词：把多余的词用斜线（\）划掉，在该行右边横线上写出该词，并也用斜线划掉。
     此行缺一个词：在缺词处加一个漏字符号（∧），在该行右边横线上写出该加的词。 
     此行错一个词：在错的词下划一横线，在该行右边横线上写出改正后的词。
     注意：原行没有错的不要改。

My friend Kate was a pretty girl whose sweet voice
drew others' attentions. Last year, she left to study at a music
school. Yesterday she called to say that she wants to see me but 
not at my house. So we fixed a time and a place and then hung. 
Today I met her at a given time and place. Greatly 
to my surprise, I found her so much changing. She
looked very sorrowful and worrying. She said she had made 
such little progress that she was almost hopeless of success. 
She wondered that whether she had been wasting her
time doing nothing. I knew he just needed some encouragement.
So I did what I could persuade her to gain her courage again.
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