TENSES

PRESENT PERFECT + ever, never, already, yet

The adverbs ever and never express the idea of an unidentified time before now e.g. Have you ever visited Berlin?

'Ever' is used

a. in questions. e.g.
Have you ever been to England?
Has she ever met the Prime Minister?

b. in negative questions e.g.
Haven't they ever been to Europe?
Haven't you ever eaten Chinese food?

c. and in negative statements using the pattern nothing.......ever, nobody.......ever e.g.
Nobody has ever said that to me before.
Nothing like this has ever happened to us.

d. 'Ever' is also used with 'The first time.... e.g.
It's the first time (that) I've ever eaten snails.
This is the first time I've ever been to England.

'Never' means at no time before now, and is the same as not ..... ever:
I have never visited Berlin

BE CAREFUL!
You must not use never and not together:

I haven't never been to Italy.
I have never been to Italy.

Position: 'Ever' and 'never' are always placed before the main verb (past participle).

Already and yet:

Already refers to an action that has happened at an unspecified time before now. It suggests that there is no need for repetition, e.g.
a. I've already drunk three coffees this morning. (and you're offering me another one!)
b. Don't write to John, I've already done it.

It is also used in questions:
a. Have you already written to John?
b. Has she finished her homework already?

Position: already can be placed before the main verb (past participle) or at the end of the sentence:
a. I have already been to Tokyo.
b. I have been to Tokyo already.

yet is used in negative statements and questions, to mean (not) in the period of time between before now and now, (not) up to and including the present. e.g.
a. Have you met Judy yet?
b. I haven't visited the Tate Gallery yet.
c. Has he arrived yet?
d. They haven't eaten yet.

Position: Yet is usually placed at the end of the sentence.