Douzhir is actually what's left over for making green bean amylum or glass noodles.

豆汁儿实际上是制作绿豆淀粉或是粉丝时剩下的东西。

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Beijing Douzhir dates back to as early as the Liao Dynasty (907-1125).

北京豆汁儿的历史可追溯到辽代(公元907 - 1125年)。

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