Sky sign
高楼广告牌
🧩 词语组成解析
sky
[skaɪ]
n. 天（空）;
vt. 将…击向空中;将…高挂;
🗣️ 情景例句
Let's do lunch sometime.
什么时候我们一起吃午饭吧。
We'll exchange presents.
我们要交换礼物。
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.
测出回声间隔的时间，便可算出该处海洋的深度。