When you swing a telephone chord in a straight line there are a discrete numbers of nodes, depending on the tension and the frequency, or in better physics terms, " energy" , you put into the system.

当你沿直线摆动一个电话和弦时， 会有离散数量的节点，这取决于你输入系统的张力和频率， 或者用更好的物理学术语， “能量” 。