Many types of clam escape predators by burrowing into the sea bed using alternating movements of their shell and of the soft, muscular foot contained within that shell.
许多蛤类利用双壳及内部柔软强健足部的交替运动在河床上掘洞来逃避天敌。
2
Packed bed reactors (100) that have a series of alternating layers of packing.
具有一系列交替填料层的填充床反应器(100)。
3
Objective to observe the clinical effects of alternating pressure relief bed mattress in the prevention of pressure ulcer (PU), and to explore the best method for application of the bed.