which form of verb is used in present perfect tense?
FORMING THE PRESENT PERFECT
The present perfect of any verb is composed of two elements : the appropriate form of the auxiliary verbto have(present tense), plus the past participle of the main verb. The past participle of a regular verb isbase+ed, e.g.played, arrived, looked. For irregular verbs, see theTable of irregular verbsin the section called'Verbs'.