问题
选择题
Many people believe we are heading for environment disaster _____ we basically change the
way we live. [ ]
A. if
B. but
C. unless
D. once
答案
答案：C
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Many people believe we are heading for environment disaster _____ we basically change the
way we live. [ ]
A. if
B. but
C. unless
D. once
答案：C
描述错误的是？（）