抽样调查的抽样方法中不包括()。
A.多级抽样
B.试点抽样
C.分层抽样
D.系统抽样
E.整群抽样
参考答案:B
_____the temperature falling so rapidly, we couldn't go on with the experiment. [ ]
A. With
B. As
C. For
D. Since
我国病毒性脑炎最常见的病原体是
A.麻疹病毒B.狂犬病毒C.肠道病毒D.EB病毒E.疱疹病毒