1. Today, enough soundings are available to enable a relief map of the Atlantic to be drawn and we know something of the great variety of the sea bed´s topography.
    现在已有足够的水深测量数据来绘制一张大西洋洋底地形图，而且我对海底地形的千变万化也有了一定的了解。

2. We know something of the great variety of the sea-bed´s topography.
    我们对海底的各种各样的地形也有了了解.