To strive, to seek, to find, and not to yield.
要奋斗,要探索,要有所发现,而不要屈服。
it is now possible not only to locate a shoal but to tell if it is herring, cod, or other well-known fish, by the pattern of its echo.
不仅能够确定鱼群的位置,而且可以根据鱼群回声的特点分辨出是鲱鱼、鳕鱼,这是人们所熟悉的其他鱼。