问题
选择题
31. _____ our earth, otherwise it will be no longer fit for us to live on.
A.Protected
B.To protect
C.Protecting
D.Protect
答案
答案:D
31. _____ our earth, otherwise it will be no longer fit for us to live on.
A.Protected
B.To protect
C.Protecting
D.Protect
答案:D