Why do vocabulary items keep repeating themselves in the activities?

Transparent Language Online uses a special Presentation Algorithm designed to show you vocabulary items multiple times. If you get a challenge wrong, the item may be shown again within a few challenges, sometimes right away. If you mistake one item for another, you will be shown both items again to clear up the confusion – even if you have never gotten that other item wrong before. This is part of what makes Transparent Language Online a robust language learning system.