copy 普通用词，含义广泛，指精确的或不精确的复制品。
duplicate 常指完全一模一样，可代替原件的复制品。
model 可指按某物式样制造、按比例缩小的模型，也可指某物未制成之前做出的模型。
reproduction 批按原物复制的产品，着重复制品与原物相似。
facsimile 含义与copy大体相同，但较文雅。
参考例句
1. Some scientists to believe the temperature of sea water can affect whale reproduction. 某些科学家相信海水温度能够影响鲸鱼的繁殖。
2. Well, many insects function as pollinators, and many plants rely on them for help with reproduction. 嗯，许多昆虫有传粉者的作用，而且许多植物依靠他们的帮助繁殖。
3. You can see a lot of needle-like, white translucent things like frost, and this is out of mycelial microbial reproduction. 你可以看到许多针状的、白色半透明的类似霜花的东西，这就是微生物繁殖出来的菌丝。
英英解释
n.
1. the process of generating offspring
2. recall that is hypothesized to work by storing the original stimulus input and reproducing it during
3. copy that is not the original; something that has been copied
4. the act of making copies
5. the sexual activity of conceiving and bearing offspring
