Is it OK to say “an important concern”?

Yes, "important issues" are appropriate in this case. New Oxford American Dictionary provides the definition of "concern" below as a noun.

(But "of" is also valid.) Using "of" and "to" to search for similar phrases does not give convincing evidence.

My main concern is this. Ok, so you only need to run a small flowchart in your mind. First of all, "What is on the earth? Through space vacuum and cosmic radiation, any creatures on Earth have passed through an eight month journey and all other creatures that have just entered the universe go from the earth to Mars Can you move it? "Okay, perhaps there are looters; this is possible; perhaps a certain thing of bacteria is possible. understood. However, if the answer is 'no', planetary protection is not necessary.

At the beginning, there is something to worry about saying "No, I am not good at", but that will also be narrowed down. In my experience, this correspondence is realistic and considerate. Perhaps because people attempt to over compensate their missing insights until self-revelation sees some of the crisis underway. This short video tells me some of the things I'm about to do. But without you, I can not. This is about working together. If you are involved in a lot of activities, please ask me more about how to cooperate. If you want to do more but do not know how to do, please contact me. In a nutshell, we can become a difference between bad people

This is a sensitive and controversial issue among people. I encourage people who think non-black people can not speak N, but for black people, if you are a good American letter from an African-American, using N I think. It is important to consider the context in which words are used in this situation. One thing that we all agree is that 'n -----' is an unpleasant language. In fact, you may come up with an argument that no one should use that word. Regardless of your race, we should use this term to manage ourselves if we really want to change as many people complain.