Defense information systems agency
un. 国防信息系统管理局\\n
🧩 词语组成解析
n. 体制, 体系；制度；系统（system的复数形式）
🗣️ 情景例句
It is.
是的。
They are so busy these days, that they don't even have time for their friends.
他们最近忙得没法和朋友见面。
He was very healthy and happy, but he could not look after himself.
他很健康，非常欢快。但不能照料自己。