what did the color of the floor use to be还是What is the color of floor used to be 哪个对?

题目

what did the color of the floor use to be还是What is the color of floor used to be 哪个对?
为什么

答案

这句话的回答形式是 the color of the floor used be to do sth……这个颜色的地板过去是做……用的所以当问问题时,把 do 提前,这里是过去式（过去曾经是）,就是第一种问法啦~如果是第二种问法要去掉used to be What...