They were unable to reproduce the results of the first experiment when they repeated it 当他们重做它时,他们不能重现再生第一次实验结果。
The bears'disappearance would probably take place as young cubs failed to survive to adulthood and females were unable to reproduce successfully 北极熊也许会因为幼仔无法活到成年,以及雌雄不能成功繁衍而消失。