Объясните грамматику Present perfect подробно И напишите примеры положительного,отрицательного предложения и вопрос

Present Perfect Tense - действие, совершившееся в прошлом, связано с настоящим, есть результат. Образуется:To have Present Simple + V-3форма I have written   Не has written   We have written   They have written I have not written   She has not written   We have not written   They have not written Have I written?   Yes, I have   No, I haven't Has he written?    Yes, he has   No, he hasn't Have you written?   Yes, you have   No, you haven't Надо запомнить типичные для Present Perfect обсто­ятельства времени: already, (not) yet, just, ever, never, since. Сравните: I have bought a book today (this week, this month) не истекший отрезок времени - Present Perfect I bought a book yesterday (last week, last month) истекший отрезок времени - Past Simple   Важные примеры: I have never been to France. Have you ever been to London? I haven't seen you for ages. I haven't met him for a long time. I haven't been to Moscow since last year.