Affirming the sufficient triggers
Denying the necessary triggers
Denying the sufficient renders irrelevant and rule falls away
Affirming the necessary renders irrelevant and rule falls away
Flash cards are definitely the way to go if you're trying to memorise them. Having the valid and invalid forms on index cards, and drilling them together helped me, that way I had to actually think about it rather than just look at it.
I have a little note pack of things I need to remember... biconditionals, valid/invalid argument forms! I review it every morning while I blow dry my hair! (multittasking FTW)
OP review the Valid Argument Form 4 in the "Some and Most Relationships." The inference (B) in this Q is very clear. (D) is reversal of the first sentence.
... to explicitly breakdown premises and conclusions since the questions I BR ... explicitly labeling the premises and conclusions is very helpful. In time ...
I mark up almost every question in LR that has an argument in it. I don't label anything using letters, but I do underline main conclusions and bracket premises.