that in its sort of steady state,

也就是处于稳态
it's natural state,

细胞的自然状态
there is this active machine

钠-钾泵这样活跃的机器
that's pumping sodium out and potassium in.

将钾钠离子泵入泵出
Then,there are these pores that when they exist and when they're open,

同时有通道蛋白这样的孔洞
are letting these molecules to leak back the other way.

开放时任由离子漏回
The pump always has to be operating

钠-钾泵必须持续工作
because the leak is always happening.

因为渗漏一直存在
Does that make sense?

明白了吗
Because you have these differences in ion concentrations

由于胞膜内外的离子浓度
across the cell membrane these--

存在这些差异
and you have the flux of molecules continuously across the membrane.

分子才可以持续地跨膜流动