---Where does John live?
---He lives on floor but he doesn’t use a lift to go up and down.
A. nine
B. the ninth
C. the nineth
D. a ninth
网友回答
A. nine
(答案→)B. the ninth
C. the nineth
D. a ninth
解析：考查序数词。句意：他住在第九层楼，但是他不用电梯上上下下。英语中表示在几楼用序数词表示，选项C结构有误，故选B。