Every austral spring, an ominous "hole" appears in stratospheric ozone over Antarctica.
每逢南半球春季，南极洲平流层中都会出现不祥的臭氧层空洞。
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But that works only with the assumption that very special conditions were in place to prevent the gas from turning into stars before a black hole had a chance to spring to life.
但是，这个理论只有做如下假设才成立，即：在黑洞有机会形成前，其特殊条件恰好阻止气体云转变成恒星。
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A large hole in the ozone layer was reported to have opened over the Arctic this spring, the first time ozone loss in the northern hemisphere has matched that in the southern.