Respectfully, the problem (I believe) is seeing it as a line.
Interleaving, isn't a "right" or "wrong", "black" or "white"... Think of it as, this topic is "less" or "more" effective.
What do I mean? Well, as someone else mentioned, studying "European Nation States" might be a good option for you. Certainly a better option than, say, Swan Diving. You should accept that "European Nation States" is the best you can do right now.
One of the hallmark traits of intelligence is the ability to "relate" unrelated things. In this way, you could - theoretically - interleave ANYTHING, you just need to think abstractly enough about it.
Interleaving, isn't a "right" or "wrong", "black" or "white"... Think of it as, this topic is "less" or "more" effective.
What do I mean? Well, as someone else mentioned, studying "European Nation States" might be a good option for you. Certainly a better option than, say, Swan Diving. You should accept that "European Nation States" is the best you can do right now.
One of the hallmark traits of intelligence is the ability to "relate" unrelated things. In this way, you could - theoretically - interleave ANYTHING, you just need to think abstractly enough about it.
Good luck