this reef does not contain the greatest variety of marine life on the planet. 这里珊瑚礁也不可能容纳全部的海洋生物
but these coral havens contain one quarter of all the marine life on our planet. 不过珊瑚礁汇聚着地球上四分之一的海洋生物
New Guinea lies in a warm tropical belt that girdles our planet around the equator. 新几内亚岛地处热带,赤道从岛中穿过
But on most tropical plains across our planet, the wet season is followed by a dry one. 然而地球上的绝大多数热带草原 在经历雨季后总是要经历旱季的
are home to some of the largest grass-eating mammals on our planet. 草原上生活着世界上最大的
This rich pasture once supported the greatest herds ever seen on our planet. 这里的大草原肥沃甘美 曾经养育着地球上最大的动物群落
Beyond the limits of the last tree, the planet is barren and ice-locked. 在最后一批树木以外的地方, 处处是冰天雪地 一片荒芜
extends one third of the way around our planet. 便横跨了地球的三分之一