The present perfect is a compound
tense that is formed with a modal verb and the perfect
Actually it works the same
in other European languages (if you care to know):
Yo he venido. = I have
Yo he comprado una casa. = I have bought a
Io sono venuto. = I have
Io ho comprato una casa. = I have bought a
Je suis venu. = I have
J´ai acheté une maison. = I have
bought a house.
The last two examples have
one thing more in common with German. They use different
modal verbs for different verb types. Participles of intransitive verbs
(the ones that don't need a direct object) are formed
with the verb to be. Participles of transitive verbs are formed with the verb to have.