斑疹伤寒病原治疗首选哪种药（）
A.青霉素
B.氯霉素
C.链霉素
D.多西环素
E.庆大霉素
参考答案：D
体层照片中的干扰影。不包括（）
A.轨迹影
B.晕残像
C.核阴影
D.体层面影像
E.层外组织模糊影
— Hi, David! How was your trip to Beijing?
— Wonderful! I had never had ________ holiday in my life. [ ]
A. a most exciting
B. a more exciting
C. the most excited
D. the more excited
