The present perfect tense describes an action that happened in the past or is still happening now.
The present perfect is formed using have (or has) and the past participle:
Note that irregular verbs form the past participle differently (e.g., eaten, bought, swum). They do not add –ed to the base.
Simply add not:
I have not confessed.
Use the regular form to ask questions:
Have they seen the light?
We have visited Burundi.
While the verb often refers to the recent past, there is no exact time limit to how long ago the action may have occurred.
I have completed two exercises and am almost done.
We have learned a great deal.
They had worked together for some time.
You have mastered the art of origami.
The time frame of the present perfect is more open ended than with the simple past. Use the simple present when you need to be more specific about the timing of the action.
That’s why you cannot use the present perfect with certain adverbs of time (e.g., yesterday):
Incorrect: I have skipped school yesterday.
Correct: I skipped school yesterday.
On the other hand, you can use the present perfect with adverbs that are less specific (e.g., already, ever, never, etc.):
I have already finished my assignment.
For more information, please see our introduction to all twelve verb tenses in English.