it's very easy to check Definition 2.

参考定义2来得更容易些
It's going to turn out it's very easy to check Definition 2.

根据定义2来分析会很容易的
It's really rather a pain to check Definition 1.

这一点可是定义1永远的痛啊
Why?

为什么呢
Because you got to keep track of these ε 's and so on,

因为你需要注意到像ε这些东西
but the fact that Definition 2 is equivalent to Definition 1...

实际上定义2和定义1是等价的
Did I say that? That's the point.

我正好说到了这是个要点
The fact that Definition 1 and 2 are equivalent, so 1 is equivalent to 2,

实际上定义1和定义2是等价的
the fact that these definitions are equivalent means

这两个定义等价的意思是
we only have to check the second definition and that's easy.

只需要根据较易懂的定义2来判断即可
So when biologists are setting up experiments

当生物学家用黄蜂或者蚂蚁
nvolving wasps or ants, or lions, or chimpanzees,

或者狮子还有黑猩猩做实验时