顾客购买某种产品时所追求的最基本的效用和利益,称为()产品。
A.有形
B.差别
C.核心
D.附加
参考答案:C
Facing the emergence, we were at a loss and none of us could ______ a solution to the problem.
A.come about
B.come out
C.come up against
D.come up with
SiO2含量最高的沉积岩是:()
A.灰岩;
B.石英砂岩;
C.页岩;
D.白云岩