[simias]

Can you explain more precisely what you want to memorize exactly?

I've only used spaced repetition for learning languages myself (vocabulary but also conjugations and declensions when applicable) and it's true that it generally works better when you can easily match something 1:1 to make both sides of the card. When you can't easily reduce something to a very simple and understandable expression it can get quite abstract and difficult to use.

For instance if you're making a deck to learn French you could make a card that says "une chaise -> a chair", no problem here. But now if you want to translate the word "encore" you have a problem because it can mean a bunch of different things in English: still, yet, even, again... Here making a card can create more confusion than nothing in my experience. It might be better to include it in short sentences demonstrating one specific meaning at a time, like "il est encore en retard" -> "he's late again".

Same thing for grammar: "je pense" -> "I think". Easy. "tu pensais" -> "you (sing. inf.) thought (imperfect)". Not so easy. For these things spaced repetition can only get you so far, you really need to practice the language "in context" to make it stick.