单项选择题
（）are used widely in the operation of warehouse and distribution center andform the basic handling device for a number of selection system.
A.Cranes B.Conveyors C.Forklifttruck D.Pallets
单项选择题 （）is the process to handle returned goods,recycle useful materials and dispose waste goods.
单项选择题 （）is the Internet commerce designed for direct communications and commercial relationship between a firmand its end customer.
多项选择题 Transport agencies include air and surface（）.
