Concern

Example Usage:

Troy is concerned about Helen.
Mrs. Worrywort is concerned about her children.
Her children concern her a lot.
Jerry's behavior does not concern me.
My main concern is finishing the job right.
It's of great concern to us.
That's none of your concern
Concerning your request, the answer is "no."
As far as I'm concerned, that's final.

Common Mistakes:

I concern my test score. (Incorrect!)
I am concerned about my test score. (Correct)
I concern about my grade very much. (Incorrect!)
I am (very) concerned about my grade. (Correct)

The word concern can be either a verb or a noun.
It is most commonly used as a verb in the passive expression: "be concerned (about)."

I am concerned.
I'm really concerned about the expense account .

Concern can also be used in the active sense:

The expense account really concerns me.
(Note: In the case, the "object" of your concern [the expense account]
is the subject of the sentence.)

If the passive/active usage of the word is confusing,
it might be helpful to think of "concern" as "bother."

Something bothers me. (S - V - O)
Something concerns me. (S -V - O)
He is bothered by the lack of courtesy.
He is concerned about the lack of courtesy.

Concern as a noun

The environment is her main concern.
There is a growing concern with pollution.

Concern in expressions

Be of (possessive) concern (to)

The Presidential election was of great concern (to many people).
That's his concern, not yours.
It's none of your concern.

As far as (I'm) concerned . . .

As far as I'm concerned, that's none of your business.

Concerning . . . (With regards to)

Concerning the issue of salary increases, my answer is still no.