Be prepared to memorize incorrect sentences so you get to the next. Drop down hints are just that, hints and are not reliable for correct answers. Suggest you go to Vietnamese Sentence discussion in main area to get a sneak preview of things to come.
I hope it is not completely dead. I am trying to learn Vietnamese because we have Vietnamese friends in the area.
I would like there to be a words list and/or stories as they do for other languages too. Especially word lists.
Duolingo keeps asking me to purchase a subscription but if they're not going to update why would I bother?