问题
选择题
We must keep _______ the classroom. [ ]
A. clean in
B. clean
C. to clean
D. cleaning in
答案
答案：A
搜题请搜索小程序“爱下问搜题”
We must keep _______ the classroom. [ ]
A. clean in
B. clean
C. to clean
D. cleaning in
答案：A