The closed system allows energy to transfer through the boundary but not mass.

闭系允许能量通过它的边界传递,但质量不行。

麻省理工公开课 - 热力学与动力学课程节选

My friends in Britain, and of courese, Britain is our oldest, one of, it's not our oldest ally but it's certainly one of our closed allies.

我在英国的朋友，当然，英国是我们最早，不，它不是我们最早的同盟国,但它是我们最紧密的同盟。

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