Our present concern is with how easily and to what extent this cycle can be modified.

=What we are concerned with is how easily and to what extent this cycle can be modified

(1)one's concern with sth 某人对某事的关心

Her concern with your money is obvious.

(2)one's concern is with 某人的关心是针对于某事

Her concern is with your money.

(3)concern oneself with sth

I didn't concern myself with politics.

我不关心政治。

He would concern himself solely with the plight of the hostages. 

他唯一关心的是人质的危险处境。