“boil over”其字面本义源于日常生活中的烹饪场景，指液体受热沸腾后溢出容器边缘的物理现象，这一用法在早期英语文献中多与厨房劳作、食物制备相关。随着语言的演变，19世纪中后期开始出现比喻义延伸，因“液体沸腾溢出”的失控状态与人类情绪、社会局势的爆发态势具有强烈隐喻关联，逐渐衍生出“情绪、矛盾或局势因无法控制而爆发”的核心语义，成为现代英语中更常用的表达。
其核心语义可明确为两类：
一是字面义“（液体）沸腾溢出”，强调物理层面的状态变化，场景集中于烹饪或自然现象；
二是比喻义“（情绪、矛盾、局势等）失控爆发、激化”，侧重抽象层面的失控状态，多含负面色彩，也指向未及时解决的问题积累后的爆发，这也是考试中的核心考查点。
The milk is boiling over.
牛奶正沸腾溢出。
If you don’t turn down the heat, the milk will boil over and make a mess on the stove.
要是不把火调小，牛奶就会沸腾溢出来，把灶台弄得一塌糊涂。
The soup boiled over when she was distracted by the phone call.
她被电话分神的时候，锅里的汤沸腾着溢了出来。
Be careful not to let the water boil over—this pot has a very narrow rim.
小心别让水沸腾溢出来，这个锅的锅沿很窄。
Finally her anger boiled over and she started hitting him.
她的愤怒最终爆发，开始动手打他。
Their disagreement finally boiled over into a fight.
他们的分歧最终爆发为一场斗殴。
Sometimes frustration and anger can boil over into direct and violent action.
有时挫折和愤怒会以直接的暴力形式爆发出来。
The students' frustration with the unfair grading system boiled over into a protest.
学生们对不公平评分制度的不满爆发为一场抗议。
The long-simmering dispute between the two countries boiled over into a diplomatic crisis.
两国间长期酝酿的争端爆发为外交危机。
The long-standing trade frictions between the two nations boiled over last month, with both sides imposing additional tariffs on each other.
两国间长期存在的贸易摩擦于上月彻底爆发，双方均对彼此加征了额外关税。
Businesses are suffering more each day in an area where the rents are extortionate, and the situation could boil over soon.
在这个租金高昂的地区，企业的困境日益加剧，局势可能很快失控。
Years of emotional neglect in the marriage finally boiled over, and they decided to separate.
婚姻中多年的情感忽视最终爆发，他们决定分居。
Racial tension finally boiled over in the inner city riots.
种族矛盾最终在市中心的骚乱中爆发。
Mistrust had been building between them for months, and it boiled over during their vacation.
几个月来他们之间的不信任不断累积，在度假期间彻底爆发。
He tried to hide his jealousy, but it boiled over when she mentioned her new friend.
他试图掩饰自己的嫉妒，可当她提到新朋友时，嫉妒情绪彻底爆发。
Their on-again-off-again relationship boiled over when he forgot their anniversary for the third time.
当他第三次忘记他们的纪念日时，这段分分合合的恋爱关系彻底爆发矛盾。
Border skirmishes intensified and eventually boiled over into full-scale conflict.
边境冲突不断升级，最终爆发为全面战争。
We kept sweeping our problems under the rug, thinking they'd go away. But they didn't—they just boiled over, and now we can't even talk without fighting.
我们一直把问题藏着掖着，以为会自行消失。但事实并非如此——它们只是彻底爆发了，现在我们甚至一说话就吵架。《婚姻故事》
Political tensions in the region have been simmering for years. One wrong move, and everything boils over.
该地区的政治紧张局势已酝酿多年。一步踏错，所有矛盾都会彻底爆发。《纸牌屋》
