问题
选择题
It's our duty to keep our environment____. [ ]
A.clean
B.cleaning
C.to clean
D.cleanly
答案
答案：A
搜题请搜索小程序“爱下问搜题”
It's our duty to keep our environment____. [ ]
A.clean
B.cleaning
C.to clean
D.cleanly
答案：A
