为了保证人流出入的方便和安全，台阶顶部平台深度不小于（）mm
A.500
B.700
C.900
D.1000
参考答案：D
该病例临床分期是
A．0期
B．Ⅰa1期
C．Ⅰa2期
D．Ⅰb期
E．Ⅱa期
—Where do you work ?
—_________.[ ]
A. I work in a school
B. I am a teacher
C. I want to be a teacher
D. I go to school every day
