Complex sentence: Unfortunately, in 1931, the great depression was at its worst, and people were not buying guitars; in addition, the patent office delayed because they had no category for the invention--was it a musical instrument or an electrical device ?
Split into simpler sentences: Unfortunately, in 1931, the great depression was at its worst, and people were not buying guitars. The patent office delayed because they had no category for the invention--was it a musical instrument or an electrical device?