The CDs are on sale! Buy one and you get completely free.A. otherB. othersC. oneD. ones

问题补充：

The CDs are on sale! Buy one and you get completely free.

A. other

B. others

C. one

D. ones

答案：

A. other

B. others

(答案→)C. one

D. ones

解析：代词用法题。One代指单数名词此处指a CD， 这些CD正在处理中！买一赠一。