concerned
used after a linking verb
The adjective concerned is usually used after a linking verb such as be.
If you are concerned about something, you are worried about it.
He was concerned about the level of unemployment.
I've been concerned about you lately.
If a book, speech, or piece of information is concerned with a subject, it deals with it.
This chapter is concerned with recent changes.
Be careful
Don't say that a book, speech, or piece of information ‘is concerned about’ a subject. Don't say, for example, ‘This chapter is concerned about recent changes’.
Don't say that a book, speech, or piece of information ‘is concerned about’ a subject. Don't say, for example, ‘This chapter is concerned about recent changes’.
used after a noun
When concerned is used immediately after a noun, it has a different meaning. You use it to refer to people or things involved in a situation that you have just mentioned.
We've spoken to the lecturers concerned.
Some of the chemicals concerned can cause cancer.
Concerned is often used with this meaning after the pronouns all, everyone, and everybody.
It was a perfect arrangement for all concerned.
This was a relief to everyone concerned.