1. The balloon suddenly popped the scared the hell out of me.2. A kid kept waving his balloon at me until I got annoyed and popped it with my pencil. Then he cried his eyes out.
 pop (a balloon, etc.) expose (a secret, etc.)pop 用在戳破氣球等的東西, expose 用在戳破祕密或謊言等
Many people in third world countries are living in unsantary conditions.