Section A
Directions: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will be spoken only once. After each question there will be a pause. During the pause, you must read the four choices marked A, B, C and D, and decide which is the best answer.
听力原文:W: Why didn't you have your geology class today?
M: Only three out of a class of twenty-five showed up. Since the professor had planned to present a complex demonstration, he decided to cancel the class until everybody could be present.
Q: Why didn't the geology class meet today?
(12)
A.The class thought the demonstration was too complex.
B.Too many students showed up.
C.The professor didn't show up,
D.The professor cancelled it.
第4题
关于CT扫描仪准直器的叙述,错误的是
A、有两个准直器,分别置于受检者前后
B、可调节CT扫描的层厚
C、减少受检者的辐射剂量
D、改善CT图像质量
E、可调节CT扫描的层距
第5题
A.可减少受检者的辐射剂量,提高图像质量
B.准直器影响像素的长度和宽度
C. 控制扫描层厚
D.准直器宽度与CT图像噪声有关
E.缩小准直器宽度可减轻部分容积效应的影响
第6题
关于CT准直器的描述,错误的是
A、可减少受检者辐射剂量
B、可减少散射线,改善CT图像质量
C、决定扫描层厚
D、有前后两套准直器
E、能吸收低能X线
第7题
CT射线辐射防护的第一关是
A、含铅的球管外壳
B、前准直器
C、滤过器
D、后准直器
E、探测器
第9题
关于CT层厚的叙述,错误的是
A、准直宽度是指CT机球管侧和受检者侧所采用准直器的宽度
B、在多层螺旋扫描方式时,决定层厚的是所采用探测器排的宽度
C、有效层厚指扫描时实际所得的层厚
D、层厚越小,误差越大
E、层厚的误差与扫描所采用的方式和设备的类型有关
为了保护您的账号安全,请在“上学吧”公众号进行验证,点击“官网服务”-“账号验证”后输入验证码“”完成验证,验证成功后方可继续查看答案!