This is the 3967th most frequent Chinese word.
人防
"People's air defense" or "civil defense."
In this sentence, '人民防空' (abbreviated as '人防') refers to specific structures or facilities intended for civil defense purposes.
城市的高层建筑通常需要设计有完善的人民防空设施。
Urban high-rise buildings usually need to be designed with comprehensive civil defense facilities.
Here, '人防' denotes knowledge or education related to civil defense.
学校开设了一门课程，教授学生对人防知识的理解。
The school has introduced a course that teaches students comprehension of civil defense knowledge.
In this context, '人防工程' incorporates the concept of building infrastructures aimed at civil protection purposes, utilizing '人防' as a component of the term.