Complex sentence: Mr. Nezzer condemns them to the furnace, but on the brink of their deaths he gives them one more chance to sing the song; still they refuse, explaining that they are taught to stand by what they believe is right.
Split into simpler sentences: Mr. Nezzer condemns them to the furnace, but on the brink of their deaths he gives them one more chance to sing the song. They get one more chance; but still they refuse, explaining that they are taught to stand by what they believe is right.