Present perfect with sein
Although the majority of present perfect German verbs use haben, some verbs use sein instead to form the present perfect tense. Frequently used verbs are: bleiben (to stay), gehen (to go), sein (to be), kommen (to come), laufen (to walk), werden (to become) and reisen (to travel).
Action verbs in the perfect tense also use sein: "We danced throughout the hall" - "wir sind durch den Saal getanzt".
Verbs that are intransitive and indicate a change in the state or condition of something also use sein: "The flower has begun to bloom" - "die Blume ist erblüht".