I am still confused on why this is invalid. My understanding is that because SAS is sufficient, she could be doing other things that are not SAS and still satisfy AAF? Since the conclusion is based on the sufficient condition, which cannot always be true, therefor the conclusion is invalid?? Could someone explain this a little more?

How can I better understand when the word "only" is being used as a group 1 indicator vs. a group 2 indicator word? It is throwing me off as I try to do the skill builder for chained conditionals.