"Kwa nini huli"
Translation:Why are you not eating
kwa nini ulikula? is 'why did you eat?'
There are different prefixes for negated verbs in the past participle form. I'll use the verb kusoma (to read) in singular and plural:
1st person: Nasom
i. (I am reading - I am not reading)
i(We are reading - we are not reading)
2nd person: Unasoma -
husomi. Mnasoma -
3rd person: Anasoma -
hasomi. Wanasoma -
Those are always the prefixes for negated verbs. For different tenses, the tense infix comes after the prefix indicating negation e.g. si
kusoma (I did not read) and si
tasoma (I will not read). Here is the same verb in the imperative form: