I said "stuff you already know", there is no point in repeating vocabulary which you already know. Some words or phrases are easier to learn, others are harder.

I said "stuff you already know", there is no point in repeating vocabulary which you already know. Some words or phrases are easier to learn, others are harder. Duolingo has no way to only work on your weekness. It's more time effective to put them on a piece of paper and to go through them a couple of times.