yet 用语肯定句表示否定以为

What's the difference between "already", "yet" and "still"?

Answer: "Already" is used in affirmative sentences; "yet" is used in negative sentences.
E.g.
1) He has already finished his homework.
2) I have not finished reading the book yet.
Note: when "already" is used in an interrogative sentence, it expresses a surprise.
E.g. Have you already seen him?
"Still" can be used in both affirmative and negative sentences. It expresses the meaning of continuation of actions and states of affairs.
E.g.
1) She still likes him.
2) I still can not understand you.
Note: The position of "still" before or after the verb makes difference in meaning.
E.g.
1) He is still standing. (continue to stand)
2) He is standing still. (=standing motionless)

“already”用于肯定句，“yet”用于否定句。
如：
1) He has already finished h