第3题: [单项选择]Questions 19 to 22 are based on the conversation you have just heard. A. He has a professional photographer take pictures for him. B. He doesn’t think he knows. C. He doesn’t have a flash attachment. D. He thinks a big camera would be too much troubl 参考答案:D 答案解析:[听力原文] Why doesn’t the man carry a camera with him [详细解答] The man said: "Carrying a
第12题: [多项选择]下列哪些属于临床试验的设计原则() A. 随机原则 B. 对照原则 C. 盲法原则 D. 重复原则 E. 编码原则 参考答案:A, B, C, D 答案解析:临床试验设计的四大原则:(1)研究对象的随机分组:随机分组的目的在于平衡实验组和对照组已知和未知的混杂因素,从而提高两组的可比性。(2)盲法应用:为避免研究对象和研究者本人的主观偏见而产生的偏倚可应用