As a result of pollution, climate change, overfishing and ocean acidification, one-quarter of global reef cover has been lost in the last 50 years and one-third of reef species are endangered.

因为污染、环境变化、过度捕捞和海洋酸化，在过去的50年中全球大约四分之一的礁石已经死亡、三分之一的礁石濒临灭绝。

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Otherwise, pick the third sock. Now the first two socks already cover both color cases. The third sock must be one of those and form a matching pair.

否则，我们在再挑选出一只袜子，我们原先挑出的袜子已经有了两种不同的颜色，第三只袜子的颜色必是其中的一种，这样，我们就挑选出了一双颜色相同的袜子。

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Now the first two socks already cover both color cases. The third sock must be one of those and form a matching pair.

否则，我们在再挑选出一只袜子，我们原先挑出的袜子已经有了两种不同的颜色，第三只袜子的颜色必是其中的一种，这样，我们就挑选出了一双颜色相同的袜子。

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But now, because the cost of college has skyrocketed, the amount Pell Grants cover is about one-third.

WHITEHOUSE: Making Higher Education More Affordable

In one-third of patients, these lesions cover more than 10% of their bodies.

FORBES: Biogen Gets Amevive Approval