Grammaticus
格勒麥蒂克斯(即Aelfric)
??? 情景例句
I know it's sudden, Robbie,
我知道這件事很突然， Robbie。
I haven't heard from him for a long time.
我很久沒有收到他的信了。
and by measuring the time interval between the taps and the receipt of the echoes, the depth of the sea at that point can be calculated.
測出回聲間隔的時間，便可算出該處海洋的深度。