balloon是個什麼單位

balloon，名詞，意思是氣球，例如：

1、We watched the balloon riding high above the fields.我們看着氣球高高地飄浮在田野上空。

2、That balloon's going to burst.氣球馬上要爆了。

3、She jumped as someone popped a balloon behind her.有人在她背後弄爆了一個氣球，把她嚇了一跳。