When a nonrestrictive clause appears in the middle of a sentence, place commas around it.

当非限制性成分在句子中间出现时，应当在它前面和后面加逗号。

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Use two commas, not one, to set off a nonrestrictive clause in the middle of a sentence.

同样的，前者由非限制性定语从句构成。 但在科技文中，你需要将其转换成名词结构。

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