What is different betweeb single stage and multi stage steam turbine?

In a single stage steam turbine the steam is run through a nozzle to give it maximum velocity, thus the blades move at very high speeds, impractical for some applications, and only some of the energy is used, about 85-90%. In multi-stage or compound turbines the steam goes through a nozzle to increase its velocity, then after going through a set of blades, it is run through another nozzle to bring the steam back up to the correct velocity. After multiple stages there is no longer enough pressure left to up the velocity of the steam. This method increases the efficiency of the turbine and also decreases wear on the components caused by the high speed of a single stage.