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单选题
Evidence collected by the spacecraft on Mars shows some present volcanic action,though the volcanoes are believed to be dormant if not dead.
A

deceased

B

departed

C

disappeared.

D

extinct


参考答案

参考解析
解析:
词语运用。火山有三种:活火山(active volcano),休眠火山(dormantvolcano)和死火山(extinctvolcano)该句逗号之后的内容指“人们认为火星上的火山如果说不是死火山至少也是处于休眠状态”,形容“死火山”应该用extinct。
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