Ever
Gli avverbi ever e never esprimono l'idea di un tempo non precisato passato (Have you ever visited Berlin?). Ever e never si collocano sempre davanti al verbo principale (al participio passato). Ever si usa:
Nelle frasi interrogative
Have you ever been to England?
Has she ever met the Prime Minister?
Nelle frasi interrogative negative
Haven't they ever been to Europe?
Haven't you ever eaten Chinese food?
Nelle frasi negative con la forma nothing + ever oppure nobody + ever
Nobody has ever said that to me before.
Nothing like this has ever happened to us.
Con l'espressione the first time
It's the first time that I've ever eaten snails.
This is the first time I've ever been to England.
Never
Never significa "mai prima di adesso" e corrisponde all'espressione not ..... ever: (I have never visited Berlin)
I haven't never been to Italy.
I have never been to Italy.
Already
Already esprime un'azione che si è verificata in un passato non precisato. Suggerisce inoltre che non è necessario ripetere tale azione.
I've already drunk three coffees this morning. (= e tu me ne stai offrendo un altro!)
Don't write to John, I've already done it.
Frasi interrogative:
Have you already written to John?
Has she finished her homework already?
Already può essere collocato prima del verbo principale (al participio passato) o alla fine della frase:
I have already been to Tokyo.
I have been to Tokyo already.
Yet
Yet si usa nelle frasi negative e interrogative e significa "(non) nel periodo compreso fra il passato e questo istante", "(non) ancora". Yet si colloca generalmente alla fine della frase.
Have you met Judy yet?
I haven't visited the Tate Gallery yet
Has he arrived yet?
They haven't eaten yet