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.
(..) - You, me, my family, the company. Come on, we haven't exactly been model citizens, Noah. - It's a pretty heavy burden for one guy. - You said you wanted to talk. Yeah. Danko's dead. Killed because of this. (..)2009 TvShow: Heroes Title: Chapter One 'Orientation/Jump, Push, Fall' Season: 4 Episode 1