Wednesday Classes

Wednesdays I have Contemporary Art Theory and Literature of the Pacific Northwest, both classes require heavy reading, both classes require that we comprehend and respond to the heavy reading with written and spoken statements that represent our understanding of the presented materials.  In one class I consistently get terrible grades on papers despite verbally demonstrating groking the materials,  in the other class I've been getting top marks.  I'm pretty confident my reading comprehension and communication skills don't differ between the two classes.  What I fail to understand is the disparity between the two.