Question type 4 WH-question (vraag met vragend voornaamwoord)
1 Interrogative pronoun (with rest of sentence) + form to be + rest sentence
What kind of animal is a platypus (vogelbekdier)?
2 Interrogative pronoun + do/does/did + rest of sentence + verb (potentially with rest of sentence)
How did you discover his secret?
3 Interrogative pronoun + first modal verb + verb (with rest of sentence. Can include yet another modal verb)
Since when have hundreds of young gamers been helped? (example is present perfect)