het onderwijs
het-wordeducation
/ɦɛt ˈɔndərʋɛis/
No plural (uncountable)
This one you just learn — no rule points to het here.
Goed onderwijs is belangrijk voor iedereen.
Good education is important for everyone.
The de/het checker covers one word. The full platform covers vocabulary, grammar and all five DUO sections.