I feel like the only time I am getting these right is when I just decide intuitively that it's right. If I overthink or try to plug things into lawgic, I change my answer and it's wrong.

This structure makes learning this type of question so easy -- I'm nervous I won't identify the right question on the test itself, but I keep getting the questions right so I'll cross my fingers that this knowledge will stick in that larger context!!

I think he's sort of reviewing the previous section, to see if you are noting the difference in action depending if you have an "if" statement vs. an "only if" statement. Essentially, they are dealt with the opposite way. And so I think this is a call back. Statements after "if" are sufficient (X), while statements after "only if" are necessary (Y).