I recommend, depending on how long you have until your test, seeing how pt 148-151 may treat you. I found the more recent ones to be a little more challenging.

fucking word choices what the hell

hello... kevin...

The replacing of all and only is definitely the best way to think of this if you are struggling with sufficiency and necessity. It follows that even if "All" in the first argument, the predicate does not require the subject to be it. "Some" narrows the scope, in turn creating a valid argument.