我们通过一架望远镜观察了停留在岩架上的一只海鹦：它在张望，思索，忽进忽退。
Through a telescope we watched the unfolding drama of a puffin on a ledge, peering over the edge, thinking better of it, retreating, advancing, retreating.
砂质物构成一个连续的海进盖层。
长广煤田上二迭统龙潭含煤岩系是由海退系列和海进系列组成的一个完整沉积旋回。
The Upper Permian System Longtan coal measure in the Changguang coal deposit is a complete sedimentary cycle, consisting of a regressive and a transgressive series.
应用推荐