在接待入境旅游团队时，全陪与地陪—起应提前( )到达接站地点，迎接旅游团。
A．10分钟
B．20分钟
C．30分钟
D．60分钟
参考答案：C
某商品标价6000元，若以9折出售仍可获利8%，该商品的进货价是多少元？
They have been skating _______. [ ]
A. for three hours ago
B. since three hours ago
C. three hours ago
D. since three hours
