题1-29图电路的戴维南等效电路图为()。
A.A
B.B
C.C
D.D
参考答案:B
下列属于变量分布数列的编制步骤的是()。
A.将原始资料按大小顺序排列,确定总体中的最小值、最大值以及全距
B.确定编制数列的类型
C.确定组数和组距
D.确定组限
E.计算各组次数,编制分布数列表
—What's the matter with Tom?
—A letter from his wife ______ an attack of homesickness.[ ]
A. held up
B. reached out
C. picked up
D. set off