duda de nivel
Me dice que he completado todas las lecciones del nivel 16. Mi pregunta es que sigue, practicar las mismas lecciones?,
You could also try the reverse course (Spanish from English), some people find it helpful. It's actually still quite good practice to keep revising the lessons after finishing the tree, but it's also time to look for other resources (books, movies, lyricstraining.com etc.).