school detention
after-school detention
administrative detention
preventive detention
A: Why are you so upset today?
A：你今天为什么这么不开心？
B: I got two detentions because I forgot my homework.
B：因为我忘了带作业，被留校察看了两次。
1) 留校察看
2) 拘留
3) 监禁
1. 留校察看；拘留；监禁
noun
1. The act of keeping someone in official custody, or a school punishment where a student must stay after school hours.
Synonym: custody, confinement, imprisonment