Forming a defensive ring around their calves, the adults present a barricade that few hunters could breach. 成牛围成圈以保护它们的小牛, 一般的猎食动物很难突破这层封锁
the stream of bats form a doughnut-shaped ring. 即在空中组成一个面包圈一样的队列
Black fly larvae anchor themselves with the ring of hooks, 蚋的幼虫靠钩环固定自己