----Your watch is so beautiful. It must be expensive----Not at all. It only $4 .A. cos

问题补充：

----Your watch is so beautiful. It must be expensive.

----Not at all. It only $4 .

A. cost B. spent C. took

答案：

解析：主语为it表示花费通常用take，本题为过去时用took，故本题选C。