At the time, spaced repetition learning was principally being implemented via flashcard systems; these systems were somewhat unwieldy since any significant study base requires many thousands of flashcards.
These systems were unwieldy because any significant study base requires many thousands of flashcards. At the time, spaced repetition learning was principally implemented via flashcard systems.
At the time, spaced repetition learning was principally implemented via flashcard systems. These systems were unwieldy because any significant study base requires many thousands of flashcards.
At the time, spaced repetition learning was principally implemented via flashcard systems. These systems were unwieldy because any significant study base requires many thousands of flashcards.