---Which floor do you live ?-The first floor. I live Room 112.A. in / onB. on / on C.

问题补充：

---Which floor do you live ?

---The first floor. I live Room 112.

A. in / on

B. on / on

C. on / in

D. in / in

答案：

A. in / on

B. on / on

(答案→)C. on / in

D. in / in

解析：考查固定搭配。住在哪一层用live on；住在哪一个房间，用live in.所以选C。