TASK DEFINITION: In this task, we ask you to rewrite a sentence in simple English without changing its general meaning. Essentially, you want to make the sentence easier to read by using simpler words, utilizing more straightforward sentence structures, and omitting non-essential information etc.
PROBLEM: In computing , a crash , or system crash , occurs when a computer program such as a software application or an operating system stops functioning properly and exits .

SOLUTION: A Computer crash is when a computer program stops running normally .

PROBLEM: The thoracic diaphragm , or simply the diaphragm , is a sheet of internal skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavity .

SOLUTION: The diaphragm is a muscle that is at the bottom of the ribcage of mammals .

PROBLEM: A death mask is a likeness ( typically in wax or plaster cast ) of a person 's face following death , often made by taking a cast or impression directly from the corpse .

SOLUTION:
A death mask is a wax or plaster cast made of a person ' s face .