问题补充:
— How about buying an iPhone 4s for your mother’s birthday?
— Oh, maybe it’s too expensive, Dad. Do you know ?
A. how much does it cost
B. how much it costs
C. how much it cost
D. how much did it cost
答案:
A. how much does it cost
(答案→)B. how much it costs
C. how much it cost
D. how much did it cost
解析:本题是特殊疑问句作宾语从句,要用陈述句语序。故选B