In this study, the researchers looked at the high-pitched barks a prairie dog makes when it spots predator.
在这项研究中，研究人员观察了土拨鼠发现捕食者时发出的高音吠叫声。
One day he and his prairie chicken friends saw a beautiful bird soaring on the currents of air, high above the mountains.
有一天，他和他的山鸡朋友看见一只美丽的鸟在天空翱翔，飞的比山还高。
One day he and his prairie chicken friends saw a beautiful bird soaring on the currents of air, high above the mountains.
有一天，他和他的山鸡朋友看见一只美丽的鸟在天空翱翔，飞的比山还高。
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