1. 重复;复制
    If you duplicate something that has already been done, you repeat or copy it.

    e.g. His task will be to duplicate his success overseas here at home...
           他在海外取得了成功，现在的任务就是要在国内再创辉煌。
    e.g. Scientists hope the work done in collaboration with other researchers may be duplicated elsewhere.
           科学家们希望与其他研究人员合作的成果可以适用于别处。

2. 复制;复印;复写
    To duplicate something which has been written, drawn, or recorded onto tape means to make exact copies of it.

duplicate

    e.g. She found Ned alone in the photocopy room, duplicating some articles.
           她发现内德一个人在复印室里复印一些文章。
    e.g. ...a business which duplicates video and cinema tapes for the movie makers.
           为电影制片商复制录像带和影带的行业

3. 完全一样的;复制的;副本的
    Duplicate is used to describe things that have been made as an exact copy of other things, usually in order to serve the same purpose.

    e.g. He let himself in with a duplicate key.
           他用一把复制的钥匙打开门进去。
    e.g. ...a duplicate copy of the loan contract.
           贷款合同的副本

4. see also: duplication