Terms for subject Economics containing in duplicate

English	Chinese
copy in duplicate	一式两份
in duplicate	一式二三、四 份 (triplicate, quadruplicate)
in duplicate	正副各一份
make out a document in duplicate	把文件誉写一式两份
We enclose our contract No. 80 in duplicate for this project, please sign the counterpart and return	并附上本项工程的第80号合同书一式两份，请签署后退回一份
We sent them the contract in duplicate	我们给他们寄去合同一式二份