Has anybody tried singing the lyrics in the DT and above?

We are all familiar with the insrumental tune which fits well the first 4 lines of each verse. But each verse then has three more lines.
Is there a "B" part to the tune we don't know? (the midi in the DT seems to just repeat the tune we know) Or, do we repeat the A part but just skip over its third phrase and go right to the end phrase?