"To be" section is marked as completed before even starting it
I just got to the point where the To Be category is accessible for the first time but it is already marked as completed, and the two following categories are accessible too.
This is because when you are just starting Duolingo with Basics 1 they go over those concepts. So it pre-strengthened but in the future you will end up strengthening it so you can refresh your memory.
I noticed this too, and I was so happy! These verbs were all over the previous lessons, so it was nice to be able to skip this. I did the "Strengthen Skills" review for it, though, just to make sure I had it down.