The earth will become worse and worse __
题型:选择题
问题:
The earth will become worse and worse ______ we do something to stop her from being polluted. [ ]
A. if
B. even if
C. when
D. unless
The earth will become worse and worse ______ we do something to stop her from being polluted. [ ]
A. if
B. even if
C. when
D. unless