unable to reproduce造句

• 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。