——I havent got a camera.——I think you should buy. Its useful for you.A. oneB. thisC. tha

问题补充：

——I haven got a camera.

——I think you should buy. Its useful for you.

A. one

B. this

C. that

D. it

答案：

(答案→)A. one

B. this

C. that

D. it

解析：one代指上文中提到的事物之中不确定的一个，而BCD都指的是确切的一个，故选A