1.already 用在肯定句中：
I have already finished my homework.
2.ever 多用于疑問句、否定句、和表示條件的附屬句子：
Have you ever seen something like this?
No such person ever existed.
If you ever see Tom,give him my kind regards.
3.never 本身就是否定意義的詞：
I never had so many problems.
4.yet 可以用在否定句和疑問句當(dāng)中：
They had not yet come.
Could you please explain why our orders haven't arrived yet?
5.just 一般用在肯定句和現(xiàn)在完成時里：
I just got back from the store.
He has received a just punishment.
.