1, concerned (adj)用做形容证书，相当于worried，表示“担心”
- Why do you keep ringing me? ~ Well, I’m concerned about you. Are you all right?
- I was very concerned that my daughter might not have proper clothing for the skiing trip.
- I was concerned for her safety as well. There have been a lot of avalanches recently.
- here was a concerned expression on his face. I knew something awful had happened.
2, concern (noun)用作名词表示“忧虑、担心”等
- There is growing concern that the climbers may have lost their lives.
- He expressed deep concern about the way in which the elections had been held.
3，concern (动词) / concerning (介词)相当于about，表示“关于”。但比about要正式
- Why are you arguing? What’s it all about? What does it concern?
- It’s about the long lunch breaks enjoyed by the senior executives.
- It concerns the long lunch breaks enjoyed by the senior executives.
- For information concerning / relating to opening hours during the summer months, contact the club secretary.
- If you want to know about opening hours in the summer months, give Joan a ring.
- A number of questions had been tabled relating to / concerning the dangers of the new vaccine.
- We had a lot of questions about people’s concerns about the new vaccine.
4,concerned用作过去分词，相当于involved / affected，表示“涉及”
- There was a brawl outside the nightclub. Those concerned were held in custody overnight. / The youths (who were) involved were held in custody overnight.
- Many have lost their savings. The pensioners concerned will receive substantial compensation / The pensioners who are affected by this will receive compensation.
5, 短语as far as I’m concerned相当于in my opinion，表示“我的意见”
- As far as I’m concerned / In my view / In my opinion, the English football supporters should not be held responsible for starting the fight.
另外，as far as x is concerned相当于concerning x，表示“就x而言”
- As far as foreign languages are concerned, I think they should be taught in primary schools.
- Concerning foreign languages, in my view it is appropriate to teach them at primary school level.