Here's a breakdown of why:
* Present Perfect Tense: This tense is formed with the auxiliary verb "have" or "has" + the past participle of the main verb.
* Irregular Verbs: These verbs don't follow the typical -ed ending for the past tense and past participle. Instead, they have unique forms.
Example:
* Regular verb: "walk" -> "walked" (past tense) -> "walked" (past participle)
* Irregular verb: "go" -> "went" (past tense) -> "gone" (past participle)
To identify irregular verbs, you need to learn their unique forms. There are many resources online and in textbooks that list irregular verbs.
Here's a common list of irregular verbs in the present perfect tense:
* have - have had
* be - have been
* do - have done
* see - have seen
* go - have gone
* come - have come
* say - have said
* take - have taken
* give - have given
* make - have made
* eat - have eaten
* write - have written
* read - have read
* know - have known
* think - have thought
* find - have found
* lose - have lost
* get - have gotten/got
* begin - have begun
* bring - have brought
* choose - have chosen
* hold - have held
Note: There are many more irregular verbs. The list above is just a small sample.
Let me know if you'd like to see a more comprehensive list or have specific questions about an irregular verb.