Complex sentence: It is discovered that, from her viewpoint, the young Lummox has been pursuing her only hobby and principal interest: the raising of John Thomases, and she makes it clear that she intends to continue doing so.
Split into simpler sentences: It is discovered that, from her viewpoint, the young Lummox has been pursuing her only hobby and principal interest: the raising of John Thomases. She makes it clear that she intends to continue doing so.