--Can I help you?--Id like to buy a present for my fathers birthday at a proper price

问题补充：

--Can I help you?

--Id like to buy a present for my fathers birthday, at a proper price but of great use.

A. one

B. anyone

C. that

D. everything

答案：

(答案→)A. one

B. anyone

C. that

D. everything

解析：本题是对代词的考查。题中one替代前面提到的a present，that通常替代前面一个已知的事物。