It is time that authorities concerned took proper steps to solve the traffic problems.上面一句话中的concern 为什么加ed啊,我不太明白.那这句话的后面为什么用took啊

it is high time that . It is time(high time)that .It is time( high time)that it is high time that的用法 It is/was time that 的用法 It is time that that可以省略吗 It is high time that something were done upon it. It is high time that something were done upon it It It is the +序数词+time that 怎样翻译呢. It is high time that 是不是It is time 的变形? It is high time that sb.should do 其中 high It is the first time that sb do sth. It is high time that的具体用法? it is the first/second.time that+现在完成时 What it is that always behind time?(谜语) IT IS THE FIRST TIME THAT 句型是什么从句 it is hign time that 后用什么时态 It goes without saying that the time is usually limited. it is the first time that i _____(visit)nanjing