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
I lie back on the bed, silent as a clam. He goes on shaving.