I get it, he signs the book....so much repeating
I get it "He signs the book" must you ask this 20 times in a chapter. There are about 50 other verbs in this chapter we could practice but you're harping on "él firma el libro".....
Seriously, I've spelled this right at least 15 times, it's time to stop repeating these
I have this issue myself -- there is a fair amount of repetition in the lesson, which is boring when it's the exact same sentence. I'd recommend reducing the lesson size (by simply removing all the third and fourth repeats of the phrase). If you want users to practice more, give more distinct phrases.
What's even more surprising is this sort of repetition in a test. If a user didn't know that phrase before the test, they'll know it during the test and then may forget it afterwards. In effect, you're giving them free questions.
I agree. I think this is one of the weakest aspects of DuoLingo as it stands. Surely it should at least be possible to code sentences with a selection of suitable words (Las [niñas/mujeres] comen [arroz/pollo/frutas/pasta/...]). That might help to reinforce more of the vocabulary, too, as some words seem to be introduced in a lesson then ignored until much later (if ever), whereas others crop up far too often.