Potential energy increases, and kinetic energy decreases. If I throw a ball in the air, on the way up, the height is increasing but the velocity is decreasing. Potential energy decreases, and kinetic energy is constant. An elevator going down at a constant speed. Potential energy decreases, and kinetic energy is constant.
Potential energy is constant, and kinetic energy increases.
A car accelerating on a flat highway. Potential energy is constant, and kinetic energy is constant. A car going 55 mph on a flat highway. An oxygen molecule of mass M is sitting at rest minding its own business. Suddenly, a cosmic ray photon passes by and adds an energy D to the molecule.