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English

An orientable surface is an abstract surface that admits an orientation, while an oriented surface is a surface that is abstractly orientable, and has the additional datum of a choice of one of the two possible orientations.

Chinese

一个可定向曲面是一个存在定向的抽象曲面,而已定向曲面是一个抽象可定向曲面,并包含了选取两个可能的定向之一的额外数据。