The present perfect tense says that an action was completed at a time before the present, and the results or consequences of the action are relevant now. The past perfect tense says that an action was completed at a time before another action happened in the past.

The present perfect tense says that an action was completed at a time before the present, and the results or consequences of the action are relevant now. The past perfect tense says that an action was completed at a time before another action happened in the past.