There is a plurality of solutions that conform to the boundary conditions, which is that the system must be bound.

这有许多解决方式,来遵守这个有界条件，那个系统必须是有界的。

麻省理工公开课 - 固态化学导论课程节选

It doesn't have to be a real container to contain it It's just an imaginary boundary there.

它不必是,一个真实的容器,只是一个想象的边界。

麻省理工公开课 - 热力学与动力学课程节选

Typically, a mountain range will be the boundary between the area of two poleis or a stretch of water, because Greece has the sea winding through it everywhere.

比如,一座山脉,就能成为一种典型的城邦之间边界,由于希腊四处邻海,一段水域也可以成为边界

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