I'm sorry Worlda, but you just can't polish a turd.

I think you meant to say "You can't make a purse out of a sow's ear" eh? Is the above one, what you teach your students? hahaha-all good fun. Now seriously, I am sure you knew the expression, as every single native speaker does, as well as countless thousands of other expressions- and this is one of the things that second language English FT's with ten degrees in English cannot match. Well, they know a few. wo shi dui de hai shi dui de?