Thanks for everything, if you ever need a favor in return, just let me know.
感谢你所做的一切,如果你需要我帮忙的话,尽管开口吧。
but that was precisely the idea adopted in some of the early instruments (seismometers) for recording earthquake waves.
但是早期记录地震波的仪器(测震仪)正是采用了这种思路。