So, that was a naturally occurring attenuated virus that could be produced into a vaccine that didn't cause the disease.

因为天花病毒存在天然的衰减病毒,这种衰减病毒可以用来,直接生产不致病的疫苗

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If they're not at the competitive output they could undercut price and take the entire market.

如果他们不按照完全竞争产量生产,就可以通过降低价格来抢占市场

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That is to say, they don't produce food.

换言之,城市人口可以不需要生产食物

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