"You are a human."
Translation:Du bist ein Mensch.
Um, it is NOT quizzing on learned material. I have NOT learned 'human' in my lessons. This is an unfair assessment. (As a US school teacher, this is quiz making 101-... test over learned material unless you are assessing what a person already knows or doesn't for lesson planning purposes.
I believe that when a new word appears, it is a differnt colour (I believe an off-yellow). If you place the cursor over the word, you will get translations -- whether it is a new word or not. This obviates the necessity of going through new vocabularies at the beginning of every lesson.