--Are you going to buy a new camera?
--Yes. But there are so many cameras that I can't decide
A. how to use B. where to sell C. which to buy
网友回答
解析：how to use如何用；where to sell哪去卖；which to buy买哪一个；句意：你打算买一部新的照相机吗?——是的，但是这儿有如此多的照相机，以至于我不能决定买哪一个。结合语句可知选C。