It's like you have a social security number or other ID number, which positively--there might be another person with the same name as you, God forbid, but you at least have your own number, which is guaranteed to be unique to you.

就好比社保号,或者其他身份号码,很有可能,有另外一个人,和你重名,希望这不要发生,但你至少有唯一的识别号,用于区分自己和他人

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