影响买方讨价还价能力的因素包括_________。
A.买方集中购买
B.买方的购买转移成本
C.产品有价格合理的替代品
D.买方行业获利状况
参考答案:A, B, C, D
"牛眼"黄斑病变最常见于以下哪种遗传性黄斑营养障碍()
A.视锥一视杆细胞营养障碍
B.卵黄状黄斑营养障碍
C.中心晕轮状营养障碍
D.Stargardt病
E.旁中心视网膜色素变性
Researchers at Children’s Hospital of Pittsburgh announced they had discovered ______ evidence that a virus is involved in what used to be called juvenile diabetes.
A. incessant B. compelling C. identical D. problematic