Once face difficult, will be very instinctively to play out full potential.

一旦面对着困难，便会很本能地把全部潜力发挥出来。

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When small fish face an extremely difficult problem-an attack, say, from several predators at once-they deal with it by forming a school.

当小鱼面临极其困难的问题时，比如说，突然遭到几个捕食者的袭击，他们会立刻形成鱼群。

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Egypt, African champions a record six times but World Cup qualifiers only once, face a difficult Group 12 assignment against the DR Congo in Kinshasa.

BBC: World Cup fates hang in balance

In our world, girls study just as hard as boys but face far more difficult choices once in the workplace.

CNN: Reproduction without sex, a liberating future

Never have we had to face so many difficult questions about our parents all at once.

FORBES: A new blog for all of us with aging parents