The ozone hole that opens every year over the Antarctic is on course to be the smallest in three decades， scientists have said.

　　科学家称，南极上空每年出现的臭氧空洞将是30年来小的。

　　Researchers say the hole is also a particularly unusual shape this year， being heavily skewed towards South America instead of centring on the South Pole.

　　研究人员说，今年臭氧空洞的形状也特别不寻常，严重向南美洲倾斜，而不是以南极为中心。

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