Tugboats
n. 拖船（等于towboat或tug）
🗣️ 情景例句
I've only been waiting for an hour.
我已经等了一个小时了。
How've you been?
别来无恙？
So it is a comparatively simple step from locating the sea bottom to locating a shoal of fish.
从测定海深到测定鱼群，这一进展比较容易。