How?
- have/has + past participle (voltooid deelwoord)
- Voltooid deelwoord:
    ww + ed => I have worked hard.      Work + ed
- onregelmatig ww (blz 163, 3rd form)      (to break-broke-broken)
   I have broken my leg, so I can't go on holiday.
- When has or have?
   shit rule: she/he/it -> has
   I/you/we/you/they -> have