问题：
[多选题]Which description() about bucket brigades is/are incorrect? ( )
ABucket brigades is a kind of zone progressive picking
BPickers be sequenced from fastest to slowest along the direction of material flow
CEach order picker carries work forward, from zone to zone, until someone takes over your work; then go back for more
DWhen the first worker completes an order, he will begin a new order at the start of the line
