echo time的用法和樣例：
例句
- The return of the echo will elapse longer time.
回聲返回所耗的時(shí)間越長(cháng)了。 - The depth of the sea at that point can be calculated by measuring the time interval between the taps and the return of the echoes.
在船體上輕輕敲擊的聲響會(huì )從海底反射回來(lái)，通過(guò)測量敲擊和收到回聲之間的時(shí)間間隔，可以計算出該處海洋的深度。
