关于订购面积的计算，通常有（）几种方法。
A.优先认购量折扣
B.累计展位数量折扣
C.团体认购数量折扣
D.差别定价折扣
参考答案：B, C, D
--- Would you please ______ your shoes on the floor?
--- Sorry. I won't do it any more.[ ]
A. not drop
B. not to drop
C. not dropping
D. no dropping
高炉冶铁所消耗的热量有（）来自燃料燃烧。
A.50%～60%
B.70%～80%
C.80%～90%
D.60%～70%
