duplication

n.复制；副本

dumpy, dun, dunce, dunce's cap, dunderhead, dune, dung, dungarees, dungeon, dunghill, dunk, duo, duodecimal, duodenal, duodenum, duologue, dupe, duple time, duplex, duplicate, duplicator, duplicitous, duplicity, durability, durable, durables, duration, duress, during, dusk, duskiness, dusky, dust, dust bowl, dust devil, dust-cart, dust-cover, dust-jacket, dust-sheet, dust-up,