单词学习：boo 动词/感叹词
boo
/buː/
嘘声（表示不满或惊吓）；发出嘘声
When the performer made a mistake, the audience began to boo, but Mr. Gu calmly continued his lecture.
当表演者出错时，观众开始发出嘘声，但顾老师平静地继续他的讲座。
单词卡片
卡片已就绪
