下列档案损坏属于自然因素的是（）。
A.遗失
B.损坏
C.被盗
D.墨迹的自然消失
参考答案：D
属于循证医学三要素的是
A．医疗部门的规定B．医师的临床经验C．患者的教育背景D．患者的经济实力E．病情的普遍程度
— Sorry, Professor Smith. I didn't finish the assignment yesterday.
— Oh, you _____ have done it as yesterday was the deadline. [ ]
A. must
B. mustn't
C. should
D. shouldn't
