Question

【题目】Many people believe we are heading for environmental disaster _________ we basically change the way we live.

A. but B. although

C. unless D. Once

Answer 1

【答案】C

【解析】句意：很多人认为我们正朝着环境灾难走去，除非我们从根本上改变生活方式。unless = if. . . not意为“如果不，除非”，只有C符合题意。