2 O present perfect é formado por: Have/has + past participle (done, seen, gone, driven, studied...)I’ve (have) decided to spend Christmas with my family.John’s (has) never seen a nativity scene.Have you ever written a letter to Santa Claus?Ann hasn’t eaten any of the cookies.
3 O present perfect é usado para: Perguntar sobre experiências, geralmente usando ever:Have you ever seen snow?No, I haven’t.Has she ever given you a present?Yes, she has.
4 Descrever experiências passadas usando already, once, twice etc. I’ve already dressed as Santa Claus.They’ve decorated the house only once.Veronica’s been to the mall twice this week.
5 Descrever a ausência de experiências usando never, ou not... yet. We’ve never been to Rio on New Year’s Eve.The kids haven’t opened their presents yet.
6 Observe que nos exemplos dados de uso do present perfect não fica claro nem é importante saber quando a ação aconteceu:I’ve been to New York many times.They’ve never had turkey.Has she ever bought a car?She’s already been asked this question.