1.be concerned about 關心;關注
It's a teacher's duty to be concerned about the students'study.
關心學生的學習是教師分內的事
2.a series of 一連串;一系列
The students have put forward a series of questions.
學生們提出了一系列問題
3.under control 在控制中;受到控制
Firemen said they had the blaze under control.
消防隊員說他們已經控制住了火勢
4.once again 再次;又一次
Once again I breathed as a free man.
我又能像個自由人一樣呼吸了