设置Wi-Fi时，确保路由器和设备之间有清晰的视线(L.O.S.)。

When setting up the Wi-Fi, make sure there's a clear ___L.O.S. between the router and your device.

由于强风干扰，我们收到了l.o.s.警报。

We received an ___l.o.s. alert due to strong wind interference.

平均住院时间为3.5天，比去年有所下降。

The average ___LOS is 3.5 days, which is lower than last year.