Complex sentence: Pete excitedly returns to the apartment to tell Mark of how he recruited a client and remarks of how he is doing very poorly in school with an 8 on his calculus test, referencing back to Mark's earlier request of a "dumb" student.
Split into simpler sentences: Pete excitedly returns to the apartment to tell Mark of how he recruited a client. He remarks of how the client is doing very poorly in school with an 8 on his calculus test, referencing back to Mark's earlier request of a "dumb" student.