pop quiz
noun [ C ] uk/ˈpɒp ˌkwɪz/ us/ˈpɑːp ˌkwɪz/
UK（有关流行音乐的）竞答比赛
a game or competition in which people answer questions on the subject of pop music, or a television show that includes such a game
US（没有提前通知的）突击测验，突击考试
a short, informal test that is given without any warning
We all remember the dreaded pop quiz from school and how it sometimes created that sinking feeling of being unprepared. 我们都记得学校的突击测验有多可怕，也记得这有时候会让人产生一种措手不及的沉重感觉。