Derocker
清石机; 除石机
🗣️ 情景例句
This is Xiao Fu speaking.
我就是。
When one is about to act, one must reason first.
凡事要先思而后行。
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。