—Can I help you?—I’d like to buy a present for my father’s birthday at a proper price but

问题补充：

—Can I help you?

—I’d like to buy a present for my father’s birthday,at a proper price,but of good use.

A. that

B. one

C. it

D. which

答案：

A. that

(答案→)B. one

C. it

D. which

解析：考查代词：A.that特指前面的可数名词单数或是不可数名词， B.one泛指前面的可数名词单数， C.it特指前面的同类同物， D.which引导定语从句，句意是：--要我帮忙吗？--我想为父亲的生日买个礼物，一个价格合理但很有用的礼物。选B。