jargoon's answer didn't help.  I'm entering a list of URLs to "get separated
files."  I just want to get a filename that's not gibberish and that contains
the important part of the URL.  I tried jargoon's suggestion,
%h%p/%n%[id:-:::].%t, and then I tried %r%h%p%N, which is as much as I could
figure out, and several other variants, and I tried all the options on the
structure list, like "site structure," but always the filename comes back as
something like "blef1c.html"  No matter what I choose, it doesn't change a
thing--the file names come back the same.  Here's an example of the kind of
URL I'm using:
<http://watchizu.gsi.go.jp/bl.aspx?id=43293055&height=2000&width=2456&dummy=0?900,800>

At the very least, I need the part after "id=" to be essentially the same--I
need all those numbers.