关于X线阳极效应的描述，错误的是（）
A.在平行于X线管长轴方向上，近阳极端有效焦点小，X线量少
B.在平行于X线管长轴方向上，近阴极端有效焦点大，X线量多
C.在垂直于X线管长轴方向上，有效焦点的大小对称相等，X线量分布也相等
D.阳极效应在临床实际工作中不必考虑
E.摄影时应注意使厚度大的组织放在阴极端
参考答案：D
解析：阳极效应在临床实际工作中不必考虑是错误的，临床上经常利用这个效应，对特殊部位摄影时应注意将厚度大的组织放在阴极端。
阅读下面的短文，根据短文内容填写表格，将信息补充完整。每空限填1个单词。 Katie Spotz is a 22-year-old girl from America. She wants to cross the Atlantic Ocean by boat. If she succeeds, she’ll be the youngest and the first American to finish the 2500-mile trip. Spotz began sailing when she was at university, but she has never tried to sail such a long way before. It will be a great challenge for her. In recent years, she has swum all the way down the 325-mile Allegheny River and traveled by bike form Seattle to Washington. Spotz knows that she may see some dangerous things during the trip. It will be very dangerous if she meets very bad weather in the middle of the sea. But she believes that she can deal with all the difficulties. “I never thought I could run 26 miles,” she said. “But once I finished it, I realized that maybe I could do something even more difficult.” Spotz wants to collect money by going on this trip. She wants to collect money for an organization called “Blue Planet Run”. The organization offers free, safe drinking water to people who need it. It will take her about three months to finish this trip. Good luck to this brave girl and best wishes to her!
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