Phanotron
[电] 热阴极含气整流管
🗣️ 情景例句
How do you like China so far?
你喜欢中国吗？
Did you have fun?
你玩得开心吗？
The further off this solid obstruction, the longer time will elapse for the return of the echo.
固体障碍物越远。回声返回所用时间就越长。