when do we use present perfect simple

It is not important when we did.
Ive been reading this book all week and Ive nearly finished.He isn't here now.Angela has bought a new flat.(I gave him your article and he has it now.).Have you seen John this morning?Im reading, harry Potter at the moment.The simple past is used to present value of annuity calculator talk about completed actions in the past.Since.30/Monday/the 14th/last week/August/1998/I graduated from university/etc.They have been coordinating network development for 5 years.
(i.e., Not in all your life up to now.).
It is used with since to talk about completed action.
I'm going to make dinner after I watch the news.3: The next use is for habits or things that we do regularly.Usually, the timetable is fixed by an organisation, not.Jimmy has gone to South America.I play tennis every Tuesday.I don't have it now.