产品生命周期理论认为,产品在市场上呈周期性特征,该周期大致分为三个阶段:即()()()
A.成熟期
B.成长
C.生成
D.衰退期
E.推广期
参考答案:A, B, D
学校食堂运来大米和面粉各6袋,大米每袋50千克,面粉每袋25千克,大米比面粉多多少千克?
— I'm going to take my dog to Quanjude restaurant tonight.
— If you do that, the waiters _____ you in. [ ]
A. don't let
B. didn't let
C. haven't let
D. won't let