完成时中什么时候用"yet"和“already"?

yet是否定和疑问句
I haven't seen him yet.
Have you seen him yet?
already是肯定句
I have already seen him.

含有"已经"的意思的时候 already
含有"还没有"的意思的时候 yet

yet是否定和疑问句
already是肯定句

疑问句和否定句用YET，肯定句用ALREADY

否定疑问用：Yet肯定用：already

yet用于否定句和疑问句
already用于肯定句