Vietnamese Tree - Informal Expressions - Lesson 3 stuck, cannot move to the next lesson
I am studying Vietnamese up to Level 14. Today (Thursday, November 3, 2016), I tried to learn more vocabularies in Vietnamese tree but in Section Informal Expressions, I tried many times to study lesson 3 Slang, but it stuck. Although I tried and tried many times but it won't move forwards. So I cannot go to lesson 4 and the following lessons. Much appreciate if anyone can help to solve the problems.
I and a few other people have had the same problem. No fix or acknowledgement yet, as far as I know, but you can access the fourth and fifth lessons by changing the URL. I don't have the link right now, but you can just change the last number in the URL to 4 or 5 to access those lessons, although it won't register the skill as completed without the third lesson.
If you want the skill complete, you can just test out, but that takes a little trial and error.