问题
选择题
We should do our best _____ the environment. [ ]
A. protect
B. to protect
C. protecting
D. protected
答案
答案：B
搜题请搜索小程序“爱下问搜题”
We should do our best _____ the environment. [ ]
A. protect
B. to protect
C. protecting
D. protected
答案：B