Not until actually with water shortage appreciate the value of water to a region.
A. facing; one can
B. faced; can one
C. faced; one cannot
D. facing; cannot one
网友回答
A. facing; one can
(答案→)B. faced; can one
C. faced; one cannot
D. facing; cannot one
解析：考查状语从句的省略式和倒装句：not until后面直接用非谓语动词做状语，说明是省略了从句的主语和be动词，而be faced with是“面对”所以是过去分词，AD是错的，not until引导的时间状语从句放在句首，主句用部分倒装，而且是肯定式。句意：直到确实缺水，一个人才能真正欣赏水对一个地区的价值。选B。