They are lousy at math--他们数学很差劲

Rat: Look at this nature show…One Zebra is attacked by a lion and the rest of the herd flees.

Rat: Why don’t they wake up and realize there’s a hundred of them and only one lion?

Zebra: They’re lousy at math.

attack vt.攻击
The enemy attacked on the left flank.
敌人向左翼进攻。
rest adj. 其余的

herd n. 兽群

flee vt.逃跑,逃走
The cat fled from the dog.
猫从狗那里逃走了。

realize vt. 察觉
The man laughed when he realized what had happened.
"当那个人意识到是怎么回事时,便笑了起来。"

lousy adj. 糟糕的，差劲的

【参考译文】

Rat: 看看这幅自然图片，斑马受到一只狮子的袭击，其余的斑马都逃走了。

Rat: 他们为什么不觉醒并且意识到有一百只河马但是只有一只狮子？

Zebra: 它们数学很差。