In the reversible case, an external pressure is essentially equal to the internal pressure.

在可逆的情况下，外部压力基本上等于内部压力。

So there's an external pressure.

它是一个外部施加的压强。

External pressure is even greater.

来自外部的压力甚至更大。

So there's our external pressure.

这一项代表外部压强。

So this is the external pressure.

这是外界压强。