red line
noun [ C ] uk/ˌred ˈlaɪn/ us/ˌred ˈlaɪn/
红线
a limit beyond which someone's behaviour is no longer acceptable
The pirates had crossed a red line, and there would be no giving in to their demands. 海盗们已经越过了红线，不能对他们的要求做出让步。
江苏热线英汉汉英双解词典包含207361条英汉翻译词条，涵盖了常用英语单词及词组短语的翻译及用法，是英语学习的必备工具。