Population information system
[计] 人口信息系统
🧩 词语组成解析
🗣️ 情景例句
sacrifices have to be made by one partner from time to time.
总要有一方必须不时做些牺牲。
Whose book is this?
这是谁的书？
has spent his lifetime studying active volcanoes and deep caves in all parts of the world.
花了毕生的精力来研究世界各地的活火山和探洞。