You really wanted:
Menu > File > Duplicate
The title of the Menu tells you what it is dealing with and most Mac programs sensibly work left to right, from the big down to the details.
You can Undo multiple times, just back up to when you had what you wanted.
Or delete the second set of copies rather than the first.
I am working with Pages '08, word processing, Snow Leopard. Sorry I forgot that, so my duplicate is under menu > Edit > Duplicate, unless I am missing something here.
I have messed with and closed the work so the undo is grayed out.
I did want a duplicate and I do have one now, but what I wanted was to get rid of the duplicate from the origional doc., that way I will have two copies of the same thing.
I was afraid to delete the second unwanted copy for fear I would delete everything...oh, I was just confused, so now did delete unwanted part and all is well. How stupid. Thanks for patience.
File > Duplicate isn't available in Pages ('08 or '09) in Snow Leopard. You'll find it in the Finder's File menu. To use it, Save and Close the file, go to the Finder, open a Finder window and navigate to the location where the file is saved. Select the file, then go File > Duplicate. Your Mac will create a copy of the file, named "Copy of filename" (or something similar.
To make a duplicate of the file while you have it open in Pages, go File > Save As..., choose a location and name for the copy, then click Save.
Note that Save As... is not available in Lion, and was returned (but, according to reports, does NOT operate in the same manner) in Mountain Lion.