Ifo
abbr. 已识别的飞行物（identified flying object）
🗣️ 情景例句
You need to complete some forms before the class.
上课之前你得填一些表格。
Is it far?
远吗？
This decline in vigour with the passing of time is called ageing.
生命力随时间的流失而衰退叫做衰老。