Wie leicht zu erkennen ist, hat das present perfect als zusammengesetzte Zeitform immer ein Hilfsverb. Wie bereits erwähnt, erfolgt die Verneinung eines Satzes über die Negierung des Hilfsverb.
Beispiel
I have already
baked the cake.
I
have not (haven't) baked the cake.*
Have you ever
been to London?
Haven't
you ever been
to London?
= Have you
not ever (=
never) been to
London?
She has worked here for
20 years.
She has
not (hasn't) worked here for 20 years.
We have just
opened a bottle of wine.
We have
not (haven't) just opened
a bottle of wine.
Have you seen
Alex lately?
Have
you not seen Alex lately?
= Haven't you
seen Alex
lately?
He has worked a lot recently.
He has
not (hasn't) worked a lot recently.
She has lived here since
1980.
She has
not (hasn't) lived here since 1980.
* Already kann hier
nicht benutzt werden, denn man sagt ja im Deutschen auch
nicht: Ich habe den Kuchen schon
nicht gebacken. Möglich ist noch
nicht, also not
yet.
Ist ein Modalverb vorhanden ("Ich habe es machen können"), dann wird das Modalverbes und nicht das Hilfsverb to have negiert.
Beispiel
I have already
baked the cake.
I
cannot (can't) have baked the cake.
She
has worked here for
20 years.
She may
not have worked here for 20 years.
We have
just opened
a bottle of wine.
We must
not (mustn't) have just opened
a bottle of wine.
He has
worked a lot recently.
He
didn't need to have worked a lot recently.
She has lived here since
1980.
She has
not (hasn't) to have lived here since
1980.
Auch hier kann man sich fragen, wie häufig solche
Sätze tatsächlich aktiv gebildet werden. Und
auch hier ist es abhängig vom Modalverb, to
can, to may und to
must sind tatsächlich ziemlich gebräuchlich
auch in einer solchen Konstruktion. Man gewöhnt sich
daran.