I got married last May.
I was single last April.
I am married now.
How long have you gotten married?
How long have you been married?
I met Mr. Carter last week.
I have met Mr. Carter for one week.
I have known Mr. Carter for one week.
Nathan became a doctor in 1998.
Nathan has become a doctor for two years.
Nathan has been a doctor for two years.
I graduated last August.
How long have you graduated?
How long have you been out of school?
The baby fell asleep two hours ago.
The baby has fallen asleep for two hours.
The baby has been asleep for two hours
I found out the news yesterday.
I have found out the news since yesterday.
I have known the news since yesterday.
(The ceremony occurred last May.)
(Status previous to last May)
(We saw each other the first time.)
(Wrong! I only met him once.)
(That's when he received his degree.)
(That's when the ceremony occurred.)
(Changed from "awake" to "asleep")