纯羊毛标志属于（）
A.联合商标
B.证明商标
C.集体商标
D.防御商标
参考答案：B
— Got any information about High School Examination?
— Well, I was trying to, but found _____. [ ]
A. one
B. no one
C. none
D. some
谈判的主体行为
