These cranes used to move exclusively on rails, but nowadays an increasing number of cranes are equipped with ordinary wheels with air-tyres and steering capabilities.翻译为：这些起重机都有专用的轨道，不过现在使用普通轮胎并且有操纵能力的起重机开始增多了，这样就使得起重机可以在码头上任意通行。
A、正确
B、错误