It is a comparatively simple step from locating the sea bottom to locating a shoal of fish . 从测量海底深度到探测海底鱼群只是较为简易的一步。
2.
A shoal of fish will do this 鱼群也反射声音。
3.
So it is a comparatively simple step from locating the sea bottom to locating a shoal of fish 因此，从测定海底深度到测定鱼群的位置这一进展相对较易。
4.
A shoal of fish will do this . so it is a comparatively simple step from locating the sea bottom to locating a shoal of fish 一大群鱼也是这样，所以，根据海底位置来判断大群鱼的位置也就相对简单了。
