is this factory____ you visited a few years ago?yes,but it isn't _____ it used to be.
A.the one,what B.one ,that C.that ,the one D.the one ,the one
答案应该是A,但D为什么不对,what 引导表语从句没错,可在D选项中,the one 可以理解为先行词,关系代词that 在做表语时可以省略啊.所以感觉D也是正确的,