—Excuse me, where is the library?—It's o
题型：选择题
问题：
| —Excuse me, where is the library? —It's on ______ floor. |
A. fourth B. four C. the fourth D. the four |
| —Excuse me, where is the library? —It's on ______ floor. |
A. fourth B. four C. the fourth D. the four |