> www.somesite.com/a/
> www.somesite.com/b/
> ...
> www.somesite.com/z/
> but i want just few letters to bi mirrored, for 
> example from 'b' to 'm' and 't'
> what should i do?
Well, you'll have to use filters, such as:
-* +www.somesite.com/b/* +www.somesite.com/c/* ...

or, because "/a/" folders are very rare, you may just 
use:

-* +*/b/* +*/c/* +*/d/* .. +*/t/*
(of course, replace '..' by proper additinal links)

This will ONLY download those dirs. You may also want 
additional images outside these directories, and 
various (css, js) files - in this case, something like:

-* +*/b/* +*/c/* +*/d/* +*/t/* +*.gif +*.jpg +*.css 
+*.js

may fit your needs!