轴长与轴率
参考答案：
晶轴系格子构造中的行列，该行列上的结点间距称为轴长。
— What's the model plane look like?
— The wings of the plane are ____of its body. [ ]
A. more than twice the length
B. twice more than the length
C. more than the length twice
D. more twice than the length
直流母线的正、负极色漆规定为（）。
A.蓝、白
B.红、白
C.红、蓝
D.黑、白
