◎ 题干
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
查看答案
◎ 解析
查看解析
◎ 知识点
    根据n多题专家分析,试题“Many people believe we are heading for environment disaster _____ we basically change theway we live.[ ]A. if B. butC. unlessD. once…”主要考查了你对  【从属连词】  等知识点的理解和应用能力。关于这些知识点的“档案”,你可以点击相应的链接进行查看和学习。