分析流行病学中最基本、最重要的研究类型是
A．现况研究
B．普查
C．抽样调查
D．病例对照研究
E．社区试验
参考答案：D
铁路运输工作人员应当坚守岗位，按程序实行标准作业，尽职尽责，保证运输安全。
Everyone including my parents, going to be at the party. [ ]
A. was
B. are
C. were
D. will
