Present Perfect

Use: actions and experiences in the past that are relevant now. Unfinished time.

Form: has/have VERB (past participle form: driven, given, made, etc.)
We
have lived in this house for twenty years. (Twenty years ago, we started living in this house. We still live in this house now.)
He
has climbed Mount Everest three times. (He climbed Mount Everest in 1988, 1999, and 2012. He might climb it again.)

Negative Form: has/have not VERB
Sara
has not completed the project yet. (Sara started the project on Monday. Today is Friday, and the project is still not done.)
They
have not completed the process yet.

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