The negative present perfect tense is used to talk about something that did not start in the past and does not continue up to the present. The formula is 'has not/have not + past participle'.
Kanusho la wakati wa sasa kamili hutumika kuzungumzia kitu kilichoanza kwenye zamani na hakikutokea hadi sasa. Fomula ni 'has not/have not + past participle'.