Let me explain further.
The scientific term for the rate of the string’s vibration is its frequency. You measure frequency in hertz (Hz), a unit that just means “vibrations per second.” The standard tuning pitch, 440 Hz, is the pitch you hear when an object (like a tuning fork or guitar string) vibrates to and fro 440 times per second.，更多细节参见吃瓜网
英國超市將巧克力鎖進防盜盒阻止「訂單式」偷竊。谷歌对此有专业解读
В Иране пригрозили расправой пользователям StarlinkВласти Ирана изъяли сотни Starlink и пригрорзили владельцам жестким наказанием