As they break out of all the soft sand, they hit the hard sand他们先是爬过软沙滩，接着爬上硬沙滩

break out逃脱

He seized every chance to break out of the Nazi concentration camp.

他抓住一切机会从纳粹集中营跑出来。

And suddenly all these crows come flocking in and start picking them off突然，乌鸦成群结队地飞来将他们一个个叼走

flock in成群结队涌到，蜂拥而至

They flee in flock in fall, leaving the empty city.

它们在秋天成群出逃,弃下空城。

People flock in from all quarters.

人们从四面八方涌来.

pick off采取

Don't pick off any of these flowers.

这些花一朵也不要采摘。

We had to pick off the fruit from the tree.

我们必须从树上摘下果实。