简述国防历史的启示。
参考答案：
经济发展是国防强大的基础、政治昌明是国防巩固的根本；国家统一和民族团结是国家强大的关键。
The idea of traveling abroad really ______ a lot of Chinese people. That's why every year witnesses
more people applying for passports. [ ]
A. sticks to
B. attends to
C. objects to
D. appeals to
为改善混凝土拌和物的流动性可以通过单纯改变用水量的办法来调整。( )
