Star dunes like these can be 300 metres high. 这些巨型沙丘高达300多米

63. so they pile the sand into dunes.
    沙子被堆成了一座座沙丘
64. These sand scenes can be hundreds of miles across.
    这些沙漠布景可宽达数百英里
65. In Namibia the winds have built some of the biggest dunes in the world.
    在纳米比亚 风塑造了 一些世界上最大的沙丘
66. Star dunes like these can be 300 metres high.
    这些巨型沙丘高达300多米
67. Grains, swept up the flanks, are blown off the crests of the ridges
    斜坡上吹起的沙粒 在沙丘顶部的边棱处飞扬
68. so it's only the tops that are moving.
    所以沙丘移动的部分只是顶部
69. The main body of these dunes may not have shifted for 5,000 years.
    这些沙丘的主体 可能已有5000多年未曾移动

来自《行星地球 第一季 第五集 Planet Earth S01E05 沙漠》第 66 行