Thank you very much 18ck! For me is one of the more difficult aspects in english are Perfect Simple, Perfect Continuous. There is no such tenses in Slavic languages.

Thank you Jeff!

Ugh! It was a lot easier to read before iTalki took out all the paragraphs!!!

I think the answer is more subtle than the previous comments say. "I read the book" is focused on the action at a specific time. "I read the book you lent me yesterday" could mean you read it all or just that you spent some time reading it, but at some point during yesterday you opened the book and spent some time reading! "I have read the book you lent me" puts more emphasis on an achievement or an act completed. In this case the speaker definitely finished it all - there's no doubt about that. You wouldn't usually give a time. In fact, if the whole sentence was "I have read the book you lent me yesterday" that would mean "You lent me a book yesterday and I have read it all". Maybe I was up all night reading it or maybe I had already read it years ago. We don't know because "I have read it" is focused on the achievement rather than the action. Other positive uses of both forms "I read my first Dostoyevsky novel while I was recovering from a broken leg" - action happening as part of a wider set of actions at some point in time "I have read the bible so I will go to heaven" or "I love that book - I've read it five times" Both examples show the speaker has finished the books and can make a claim to know about them. And here are some examples in a negative context "Is the new book by Margaret Atwood good?" "I don't know - I haven't read it" Means the speaker has never read the book and is not qualified to judge. "I took a book on holiday but the tent blew away so I didn't read it" Here the speaker is saying that _at_ _that_ _specific_ _time_, he didn't read the book. But that doesn't mean he hasn't read it, only that he didn't read it on holiday. If we wait a few seconds he might complete the sentence... "I took a book on holiday but the tent blew away so I didn't read it until I got home" And then we would know He has read the book. This is one of the more difficult aspects of past tense in english so I hope I have explained it well!

I have read = you have finished reading the book now. I read = you did the action of reading but did not finish reading it.