"The sheets are on the bed."
Translation:Le lenzuola sono sul letto.
Unfortunately, there's a bunch of examples: http://italian.about.com/library/fare/blfare169a.htm http://www.arnix.it/free-italian/italian-grammar/plural-of-italian-nouns-by-changing-the-ending.php http://tutorino.ca/grammatica/2007/8/7/irregular-italian-nouns-3-nouns-that-change-gender-in-the-pl.html
I like that idea. I have previously floated the idea that things like this (optional learning sections) could be bought with lingots, which is nice because it's optional (doesn't force the section on others) and would give one something to look forward to when spending one's lingots :-)