El present perfect une el pasado con el ahora. Se forma como nuestro he comido: have / has + participio (has con he, she, it).

• I have visited London. — I've visited London. — He visitado Londres.
• She has lost her keys. — She's lost her keys. — Ha perdido las llaves.

En los verbos regulares, el participio es igual que el pasado: worked, visited, finished, travelled. En los irregulares, a veces hay una tercera forma:

Verbo	Pasado	Participio
be	was / were	been
go	went	gone
do	did	done
see	saw	seen
eat	ate	eaten
drink	drank	drunk
find	found	found
have	had	had
buy	bought	bought
lose	lost	lost

La pregunta y la negativa usan el propio have, sin did: Have you eaten? — Yes, I have. / No, I haven't. Y ojo: she's puede ser she is o she has — she's lost es she has lost.