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

Present Perfect Tense - действие, совершившееся в прошлом, связано с настоящим, естьрезультат.
Образуется:To have Present Simple + V-3форма
I have written   Не has written  We have written   They havewritten
I have not written   She has notwritten   We have not written   They have not written
Have I written?   Yes, I have   No, I havent
Has he written?    Yes, he has   No, he hasnt
Have you written?   Yes, you have   No, you havent
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 havent seen you for ages.
I havent met him for a longtime.
I havent been to Moscow sincelast year.