Student or Learner
I have two questions to ask:
Whenever she heard a knowck at the door, she would fist go to check on the door.
Can I say "to check on who it was"?
The girls the author concerned with are those who are definitely different from their parents.
Can I use "concerned for or concerned with"?
Looking forward to hearing from you.
Thank you in advance.
1. In this example, both the original and your suggestion, I would not use the word "on".
2. This example simply does not make sense in either construction. The author is not "concerned" with or for anything. His writing "concerns" the subject. For an author to be concerned "for" something, that means he has a sense of concern regarding the well-being of the object of his concern. It does not mean he is simply writing about the subject (for whom he may have no need to worry about [to be concerned for] ).