間違いやすい単語

yet
疑問文で「もう」。否定文で「まだ」(not yet)。肯定文では already を使います。

already
肯定文と疑問文で「すでに」。否定文では not yet を使います。

Have you eaten lunch yet?
I have not eaten lunch yet.
I have already eaten lunch.
Have you eaten lunch already?