SORRY.CRM is all about BEHAVIOUR and ATTITUDE
So let me make it practical since you can't seem to think for yourself.
SafetyPee is close in his guess of the difference between active and passive listening but he has them reversed.
Passive monitoring is the canned response. Active monitoring (AM) is an engaged
mental response. It doesn't have anything to do with talking but with attitude. When the PM is engaged in AM he isn't merely repeating data to the PF (though he is doing that) he's also engaged in probabilistic and even possibility thinking. He engaged in a mental process of "what does this data that I am relaying to the pilot actually mean". How does it fit within the context of the situation the plane is in.
Passive monitoring is concerned with what is happening exclusively. Active monitoring is concerned with what is happening, why is it happening, and what are the future implications. And it's doing so
consciously. Many skilled pilots do this unconsciously and they call it "intuition" or even "experience". But when we break down what they are doing at the mental level what separates them out is their level of engagement with the situation. They are not merely passive receptors, middle men, a second pair of eyes. They are a second brain interacting with the world around them in ways that enhance the safety of the plane.