Ssts
abbr. signaling and supervision techniques study 信号传送与监听技术研究; space surveillance and tracking satellite 空间监视与跟踪卫星; space-based surveillance and tracking system 天基监视与跟踪系统
🗣️ 情景例句
I started traveling twenty-four hours ago.
从出门到现在已经二十四小时了。
You're welcome.
不客气。
This, however, means nothing.
但是，这没有什么关系，