On the bottom of most plastic packaging, there's a small triangle with a letter or a number written inside.

在大多数塑料包装的底部都有一个小三角形，里面写着一个字母或数字。

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On the bottom of most plastic packaging, there's a small triangle with a letter or a number written inside.

在大多数塑料包装的底部都有一个小三角形，里面写着一个字母或数字。

youdao