quarantine signal

例句：

1. 1. The quarantine signal was sent to the airport to prevent any further spread of the virus.
   为了阻止病毒进一步传播，已经发送了检疫信号给机场。
2. 2.The quarantine signal has been lifted, allowing people to return to their normal lives.
   检疫信号已经解除，人们可以恢复正常生活。
3. 3.The quarantine signal is a crucial measure in preventing the spread of infectious diseases.
   检疫信号是预防传染病传播的关键措施。