I hate change. I really do. While processing a crit from my new CP, I discovered one of the many grammar lessons drilled into my head for most of my young life is no longer a rule. I'm speaking of the comma-before-too rule. I was always taught that anytime you're using too to mean also , you should put a comma before it (or commas around it if it comes in the middle of the sentence). According to the CMoS website Q&A , that's no longer true. From their site: