来自李凯里的问题
【About2000yearsago,theworld'spopulationwasp-------about250million.】
About2000yearsago,theworld'spopulationwasp-------about250million.


【About2000yearsago,theworld'spopulationwasp-------about250million.】
About2000yearsago,theworld'spopulationwasp-------about250million.
probably
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