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单选题
Freshwater fish stocks are vulnerable or endangered because of ______.
A
shortage of freshwater.
B
pollution and changes in their living environment.
C
fertilizer run-off.
D
closed chemical works.
参考答案
参考解析
解析：
从录音最后提到的超过五分之一的淡水鱼已经变得“vulnerable or endangered because of pollution or habitat modification”，可见污染和生存环境的变化是淡水鱼变得易受伤害或濒临灭绝的原因。
【录音原文】
Sheer shortages of freshwater are not the only problem. Fertilizer run-off and chemical pollution threaten both water quality and public health. More than one fifth of freshwater fish stocks are already vulnerable or endangered because of pollution or habitat modification.
从录音最后提到的超过五分之一的淡水鱼已经变得“vulnerable or endangered because of pollution or habitat modification”，可见污染和生存环境的变化是淡水鱼变得易受伤害或濒临灭绝的原因。
【录音原文】
Sheer shortages of freshwater are not the only problem. Fertilizer run-off and chemical pollution threaten both water quality and public health. More than one fifth of freshwater fish stocks are already vulnerable or endangered because of pollution or habitat modification.
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