听力原文

Chiru, or Tibetan antelope, have arrived for the winter rut.
长角羚或叫藏羚羊已经到了冬季的发情期。
In the energy-sapping thin air, the males must try to control groups of females by constantly rounding them up and corralling them.
在这样耗能的稀薄空气当中，雄性还必须经常地围着成群的雌性跑，以使她们在自己的控制之下。
But the chiru have an advantage. Their red blood cell count is twice as high as ours, sufficient to supply their muscles with oxygen even at this extreme altitude.
但是藏羚羊也有优势，他们的红血球数量是我们的两倍，即使在如此高的纬度 也足以为他们的肌肉输送氧气。
Nevertheless, it's hard work keeping his harem in check, and the male's life is about to get even harder.
然而，想要控制住这么一大群家眷并不容易，甚至有时雄性的生活会更加艰难。
Another male is gearing up to steal his females. With their rapier-like horns,the males won't risk fighting unless they really have to.
另一只雄性垂涎于它的家眷们，除非逼不得已雄性一般不会冒险用它们剑一样锋利的角搏斗。
But if neither backs down, conflict is inevitable. Some of these fights end in death.
但如果双方都不退让 大战就不可避免。有时甚至不死不休。
While the males fence, the females look on.
在雄性抵抗的时候，雌性就在一旁看着。
Injured and weakened by the battle, the loser will be an easy target for the predators and scavengers that patrol the wilderness.
虚弱受伤的失败者很容易成为在荒原上游弋的食肉动物和食腐动物的目标。
Out here there's little room for mistakes.
在这里生存不容许有任何失误。

重点讲解

重点讲解：
1. round up
使聚拢；使聚集；
eg. He had sought work as a cowboy, rounding up cattle.
他找了一份放牛的差事，负责把牛赶到一起。
eg. I round up a few friends for a party.
我找了几个朋友聚了聚。
2. keep in check
控制；
eg. He's found someone with a bit of fight to keep him in check.
他发现有个厉害的主儿能镇住他了。
eg. The prisoners must be kept in check.
囚犯们必须严加管束。
3. gear up
为…作准备；为…作好了准备；
eg. I am now in high school, it's time gear up for study.
现在我是一名高中生了，该是努力学习的时候了。
eg. The ban was lifted last month, but aid agencies say it takes time to gear up.
此禁令已于上月取缔，但是援助机构称需要时间进行准备。
4. back down
放弃（主张、要求、承诺等）；打退堂鼓；
eg. He had to back down on plans to backdate the tax changes.
他不得不放弃追溯税收调整的计划。
eg. After being confronted with our evidence, the other side had to back down.
面对我们的证据，另一方不得不退让。
5. room for
机会；余地；可能性；
eg. The intensity of the work left little room for personal grief or anxiety.
高强度的工作使人几乎没空去悲伤或者忧虑。
eg. There's lots of room to express yourself creatively.
有很多让你展现创意的机会。