1. Lend me the book after you read it.
2. Lend me the book after you have read it.
My grammar book say 2 is grammatical and I wonder why not 1.
Your thanks are appreciated, wotcha, but you don't need to send them in a separate post or quote our replies back to us.
We are all happy to accept a simple click on the Like button as your acknowledgement of our help.