There are so many kinds of pens in the shop.I can't decide __.A.t_英语解答

There are so many kinds of pens in the shop.I can't decide __.
A.to buy what B.to buy which C.what to buy D.which to buy
请高手给个确切的答案,再讲下其中的语法知识,

人气：132 ℃　时间：2019-10-18 23:10:10

解答

选D,店里的笔太多了,我不知选哪个.这是疑问词+ 不定式结构.例如,I don't know where to go.
祝你进步哟!