»
you've
they have
»
they've
Negative
Subject
Auxiliary
not
Verb (past participle)
I
have
not
seen
this film yet.
You
We
You
They
He/She/It
has
The contracted forms haven't and hasn't are often used instead of have not and has not in spoken and in informal written language.
Interrogative
(Question word)
Auxiliary
Subject
Verb (past participle)
(How many times)
have
I
seen
this film?
you
we
you
they
has
he/she/it
Related topics:
The forms of the participle
Subject-auxiliary inversion in questions
Appendix: irregular verb forms
Present perfect for past events
The present perfect tense is used for past events when the exact time is not mentioned either because it is not known or it is not important. The emphasis is on the fact that the events happened before the time of speaking:
I'
ve been
to China.
I'
ve seen
that film before.
But if we say when something happened, we use the past simple:
I
went
to China in 2011.
I already
saw
that film last week.
We also use the past simple if we ask when something happened in the past:
"Have you ever been to China?"
"Yes, I have."
"When
did
you
go
there?"
"Have you seen that film before?"
"Yes, I have."
"When
did
you
see
it?"
Quotes:
Education is what remains after one has forgotten what one has learned in school. - Albert Einstein
I have never met a man so ignorant that I couldn't learn something from him. - Galileo Galilei
What you have become is the price you paid to get what you used to want. - Mignon McLaughlin
I have not failed. I've just found 10,000 ways that won't work. - Thomas Edison
Related topics:
Past simple for completed actions in the past
Past perfect for actions completed before a point in the past
Future perfect for actions completed before a point in the future
Present perfect for recent events with a result in the present
The present perfect tense is used for recent events that have a result in or an effect on the present moment:
Someone
has opened
the window.
(the window is open, and it is cold inside)
Tom
has broken
his leg.
(his leg is broken, and he can't walk)
If there is no connection between the action and the present moment, the past simple is used:
Someone
opened
the window to let in some fresh air.
(the window is now closed, or we don't know whether it is closed or not)
On the day before the match, Tom
broke
his leg.
(his leg is not broken any more)
Present perfect with an incomplete period
The present perfect tense is used to express actions happening in an incomplete period of time. An incomplete period is one that includes the present moment, that is, the time of speaking. This period can be implied or expressed with a time expression (today, this week, this year, ever, never etc.):
I
haven't smoked today
.
I'
ve lived
here
all my life
.
Have
you
ever been
to China?
(in your life)
My uncle
has written
several plays.
(in his life, supposing he is still alive)
He
has never worked
as a waiter.
(in his life)
If the action happened in a completed period of time (one that does not include the time of speaking), the past simple tense is used. This period can be implied or expressed with a time expression (yesterday, last week, last year, between 1905 and 1910 etc.) or a clause:
I
didn't smoke
yesterday.
I
lived
in this house when I was a child.
(I am not a child any more)
Did
you
go
to China when you were working as a flight attendant?
Shakespeare
wrote
numerous plays.
(in his life, he is dead now)
He
worked