10kV配电室应用最为普遍的断路器操作机构为（）
A.永磁式
B.手力式
C.液压式
D.弹簧储能式
参考答案：D
Which of the following is not among the basic features of a relational database
A． It does not matter what order the rows are in.
B． It does not matter what order the columns are in.
C． Different columns should have different column names.
D． Different columns should have different data types.
轴型皮瓣的长宽比例为（）
A.1.5：1
B.2：1
C.3：1
D.4：1
E.无限制
