+ I have worked you have worked he/she/it worked etc
? have I worked have you worked has he/she/it worked? etc
- I have not worked you have not worked etc
For contractions (I've, he's, haven't)
An irregular verb
I have seen etc
have I seen
I have not seen
To make present perfect, put have/has with the past participle(worked, seen etc)
Regular past participle end in -ed, like simple past tenses.
With irregular verbs, the past participle is often different from the simple past tense.