and the biggest source of sand and dust in the entire world. 也是全世界最大的沙尘源
But it is the only source of water, 可是这是唯一的水源
The source of these toxic fumes lies several miles below. 这些毒气的源头位于地下几英里处
These flooded shafts are the region's only source of open fresh water. 这些水潭是整个地区 唯一的露天淡水资源
finding a regular and reliable source of food. 即找到长期而可靠的食物资源
Insects seem irresistibly drawn towards the source 昆虫总是禁不住光源的诱惑
Eventually, over 4,000 miles from its source, 最终 在经过4000英里的流程之后
the rivers are not only a vital source of drinking water, 河流不仅是唯一能解渴的重要水源