The 'burden of proof' is on the plaintiff, since the defendant is presumed innocent until proven guilty. [=the plaintiff must prove that the defendant is guilty]
The 'tax burden' has been falling increasingly on the middle class. [=middle class people have been paying a greater portion of taxes]
For the rest of his life he 'was burdened' with the knowledge that he had done nothing to help them.
(..) The bears go straight to the dealers. Yeah, and the rabbits go to the man in the Narrows. - What's the difference? - Ignorance is bliss, my friend. Don't burden yourself with these secrets of scary people. Hey. Steiss. Steiss? MAN: What? (..)2005 Batman Begins