Wat heb je geleerd gisteren? Sounds ok. Why is that wrong?
Sounds fine to me (Source: I'm Dutch). You can be both singular and plural and you can put gisteren before or after geleerd. Report it.
Participles almost always go to the end of the clause in Dutch, much like German. However, Dutch is less strict than German in cases of prepositional phrases. Gisteren is an adverb though, so geleerd would come after it.
Wat zijn jullie gisteren geleerd? what is wrong with this? I read that gisteren is always used with zijn/is. confusing
wat heb je gisteren geleerd - is also a correct answer. Please update.