Given the task definition and input, reply with output. 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.

A four-stroke ( also four-cycle ) engine is an internal combustion ( IC ) engine in which the piston completes four separate strokes while turning the crankshaft .

The four-stroke engine is an internal combustion engine .