Trichechiformes
海牛形亚目
🗣️ 情景例句
But first things first.
但事有先后。
I was impressed very much.
我有深刻的印象。
and near its lower reaches there is a long tailing-off which is almost certainly the result of material transported out to deep water after being eroded from the continental masses.
在这个地带的低处是很长的一段尾沙地段，基本上可以断定这个地段是大陆块体上侵蚀下来的物质被水冲到深水处形成的。