If you look at the reasons Tom Robinson suspected Maybella's father of beating her, that should help. Have a look at Tom's story of what happened and all the evidence from his side, including Maybella having bruises on the right side of her face, and her father being left handed, and no medical help was called for even though she was covered in bruises.
I hope this helps a little :)
It is a complex sentence because it is an independent idea and a dependent idea in one sentence.
It means "with or "thoroughly"
So the answer would be with.
Is this referencing the roaring twenties?