Questions & Answers about Har du ikke sett kurven?
Because this is a yes/no question. In Norwegian main-clause yes/no questions, the finite verb comes first.
- Statement: Du har ikke sett kurven.
- Question: Har du ikke sett kurven?
So har moves to the front, just like English often does with have in Have you...?
This is the present perfect tense.
- har = the auxiliary verb have
- sett = the past participle of å se = to see
So har sett means have seen.
The sentence is asking whether the person has seen the basket up to now, not just at one specific finished moment in the past.
Sett is the past participle of the irregular verb å se.
Some forms of å se are:
- infinitive: å se
- present: ser
- past: så
- past participle: sett
So:
- Jeg ser = I see
- Jeg så = I saw
- Jeg har sett = I have seen