Unobservability
不可观察性
🗣️ 情景例句
We have several package tours you may choose, from ten days to three weeks in Europe.
我们有几套欧洲旅游计划选择，时间从10天到3个星期。
It's a deal.
一言为定。
My brother has never been abroad before, so he is fending this trip very exciting.
我弟弟以前从未出过国，因此，他觉得这次旅行非常激动人心。