—? —I want to buy a dress. A. What do you wantB. What do you doC. What can I do for youD.

问题补充：

—? —I want to buy a dress.

A. What do you want

B. What do you do

C. What can I do for you

D. Can you help me

答案：

A. What do you want

B. What do you do

(答案→)C. What can I do for you

D. Can you help me

解析：句意：——我能为你做什么？——我想买一件裙子。A. What do you want你想要什么。 B. What do you do你是做什么工作的；C. What can I do for you我能为你做什么？ D. Can you help me你能帮助我.

根据I want to buy a dress.可知前面是售货员对顾客说的话，问顾客有什么可以为他效劳的，故选C。