Last week the scientists warned that a third of the world's polar bears could disappear in the next 40 years.

上周，科学家们警告说，世界上三分之一的北极熊可能会在未来40年里消失。

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Last week the scientists warned that a third of the world's polar bears could disappear in the next 40 years to melting Arctic sea ice.

科学家们上周警告称，随着北冰洋冰面的消融，全球三分之一的北极熊可能在未来40年内消失。

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The scientists warned that the recovery of coral cover is expected to take a decade or longer, but it would take much longer to regain the largest and oldest corals that have died.

科学家警告说，大堡礁珊瑚恢复生机大概需要十年或更长时间。不过，对那些已死亡的最大和最老的珊瑚群来说，恢复生机要花费更长的时间。

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The scientists warned that the recovery of coral cover is expected to take a decade or longer, but it would take much longer to regain the largest and oldest corals that have died.

科学家警告说，大堡礁珊瑚恢复生机大概需要十年或更长时间。不过，对那些已死亡的最大和最老的珊瑚群来说，恢复生机要花费更长的时间。

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