The fishermen know the approximate time of year when they will be allowed to fish, but on any given day, one or more field biologists in a particular area can put a halt to fishing.

渔民们知道一年中允许捕捞的大概时间段，但是在某些日子，一个地区可能有一个或多个实地生物学家中止捕鱼活动。

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Zhu Keming never thought he would be a hero one day, but he was just that on Saturday when he saved the lives of six runners during the mountain marathon in Baiyin, Gansu Province, in which 21 people lost their lives.

朱克铭从未想过自己有一天会成为英雄，但他恰恰在周六，在甘肃省白银市举办的山地马拉松比赛中拯救了6名参赛者的生命，在这场比赛中，有21人丧生。

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One day her mother asked her: "But Helen, why do you never wear glasses when you are with Jim?"

有一天妈妈问她：“海伦，你和吉姆在一起时为什么从不戴眼镜？”

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ESpeed's share price fell after Sept. 11, 2001, of course, but when compared with just one day earlier, its shares are up 62%.

FORBES: Magazine Article

But I remember one day when we returned to the apartment and she wasn't waiting in the hallway as we came up the stairs.

NPR: Excerpt: 'Trauma'

Ferrell isn't breaking new ground, but one day -- when he's branching out to play psycho killers and getting in touch with his inner Thespian -- we'll look back on his clowning period and wonder why he would want to do anything else.

CNN: Review: 'Blades of Glory' scores hilariously