定语从句能直接做表语吗?

定语从句修饰名词或代词,这句话变成陈述句就是This is factory ____ you visited the other day?如果用that那么“factory”前面要加冠词“a”,这样“that”才修饰“a factory”,是定语从句,但是题目中没有“a”,所以用“the one”