Complex sentence: A turbojet does not rely purely on the motion of the engine to compress the incoming air flow; instead, the turbojet contains some additional rotating machinery that compresses incoming air and allows the engine to function during takeoff and at slow speeds.
Split into simpler sentences: A turbojet does not rely purely on the motion of the engine to compress the incoming air flow. Instead, the turbojet contains some additional rotating machinery that compresses incoming air and allows the engine to function during takeoff and at slow speeds.