北极冻原是指北极点周边的地区,是世界最高的地方.The arctic tundra is at the top of the world around the North Pole.冻原天鹅的北美洲亚种,以其柔和的鸣叫著名.North American subspecies of tundra swan having a soft whistling note.由永久冻土组成的北极冻原正在逐渐融化.Permafrost - the fr...
水位涨得够高了，他们可以继续向上游航行。The water rose high enough for them to continue upstream.这艘船顺尼罗河向上游航行.The ship is sailing up the Nile.探险者们谨慎地把独木舟向上游划去.The explorers paddled their canoe cautiously upstream....