How about pair?[ ]
A. a
B. this
C. these
答案:B
(73)is a category assigned to products or services having the same functional use but different technical characteristics.It is not same as quality.
A.Problem
B.Grade
C.Risk
D.Defect
辨析:我国人民民主专政的特点和优点集中表现在它是民主与专政的统一。