Complex sentence: Bart Simpson shows Stewie his slingshot, and teaches him how to skateboard, but is then bullied by Nelson Muntz, so Stewie takes revenge by kidnapping and torturing Nelson.
Split into simpler sentences: Bart Simpson shows Stewie his slingshot, and teaches him how to skateboard. When Bart is bullied by Nelson Muntz, Stewie takes revenge by kidnapping and torturing Nelson.