流感的潜伏期为（）
A.3～5天
B.1～3天
C.5～7天
D.数小时
E.12～24小时
参考答案：B
Spring Festival is the most important festival in China and an occasion ____ all family members
get together, just like Christmas in the West. [ ]
A. where
B. when
C. that
D. which
除下列哪项外均为中晚期食道癌的肉眼类型()
A．髓质型
B．蕈伞型
C．平坦型
D．溃疡型
E．缩窄型
