一级普通消防站三节拉梯配备标准是（）。
A.1架
B.2架
C.3架
D.4架
参考答案：B
﹣Peter, could you tell me ___________?
﹣He is under the tree over there.
A. where your father is B. what your father is C. how your father is
一组数据的标准差，反映这组数据的（）。
A.分布范围
B.差异大小
C.取值水平
D.集中位置
