see
seen
You/travel/São Paulo.
You've travelled to São Paulo.
They/not hear/the news.
They haven't heard the news.
You/ever/eat caviar
Have you ever eaten caviar?
I have go to the doctor's.
WRONG
I have gone to the doctor's.
be
been
I/be/busy
I've been busy.
I/not finish/my report.
I haven't finished my report.
They/already/finish
Have they already finished?
She has been very tired lately.
RIGHT
have
had
She/buy/a house.
She has bought a house.
I/not get/your message.
I haven't got your message.
She/ever/have/any problem
Has she ever had any problem?
I've never taked that bus.
WRONG
Right: I've never taken that bus.
eat
eaten
We/be/friends/since I was a kid.
We've been friends since I was a kid.
Maria/not meet/the new intern.
Maria hasn't met the new intern.
You/already/write/the email
Have you already written the email?
It have been a difficult year.
WRONG
Right: It has been a difficult year.
go
gone
He/do/the report.
He has done the report.
It/been/easy.
It hasn't been easy.
They/ever/be/in France
Have you ever been in France?
She haven't called her dad yet.
WRONG
Right: She hasn't called her daddy yet.