Expression: Boil over

A small subway fare increase in Chile sparked nationwide riots not because of the cost itself, but because it was the final trigger for years of simmering frustration with inequality and government distrust. This moment—when long-suppressed emotions erupt uncontrollably—is what the English expression 'boil over' describes. The phrase captures the sudden, messy loss of control in emotions like anger or tension, whether on a personal level or between nations. The episode uses the Chilean protests and U.S.-China tensions over Taiwan as real-world examples, showing how 'boil over' applies when pressure builds to a breaking point. The lesson also highlights how Plain English’s platform helps learners instantly translate key vocabulary into nine languages, making listening more accessible and effective.