Ever
副詞 everと never は、今より前の未確認の時間の概念を表現します。 (Have you ever visited Berlin?)'Ever'と 'never' は、常に主動詞(過去分詞)の前に置かれます。Ever の使い方：
疑問文で
Examples
Have you ever been to England?
Has she ever met the Prime Minister?
否定疑問文で
例
Haven't they ever been to Europe?
Haven't you ever eaten Chinese food?
nothing+ever や nobody+everのパターンを使った否定分で
例
Nobody has ever said that to me before.
Nothing like this has ever happened to us.
'The first time'と共に
例
It's the first time that I've ever eaten snails.
This is the first time I've ever been to England.
Never
Never は、 今までに一度もないを意味し、 not ..... everと同じです： (I have never visited Berlin)
I haven't never been to Italy.
I have never been to Italy.
Already
Already は、今より前の未確認の時間に起こった行動を述べ、繰り返す必要がないことを表します。
例
I've already drunk three coffees this morning. (= and you're offering me another one!)
Don't write to John, I've already done it.
これは質問文にも使われます：
Has she finished her homework already?
Already は主動詞(過去分詞) の前に置いたり、文章に終わりに置くことも出来ます：
I have been to Tokyo already.
Yet
Yetは否定文や疑問文に使われ、 今より前と今の間の時間にまだ（...ない）、現在を含む時までにまだ (...ない) を表します。Yet は通常文章の終わりに置かれます。
例
Have you met Judy yet?
I haven't visited the Tate Gallery yet
Has he arrived yet?
They haven't eaten yet