Cách sử dụng
The expression "when the balloon goes up" means when a situation becomes critical or when trouble starts. It has its origins in military signaling, where balloons were used to communicate information about enemy movements. Nowadays, it is commonly used to refer to any situation that suddenly becomes difficult or dangerous. For example, you might say "I always keep some emergency funds on hand, just in case the balloon goes up and I need to make a sudden move." It is an informal expression used in casual conversations.