"fish" 复数: 我们一般不用"fishes".[一种鱼但许多条...]
a) Fish are cold-blooded vertebrate animal that live in the water.
b) Salmon is a fish.
c) I caught six fish in the river yesterday.
2. 但是,当描述<许多种类>的鱼时我们才用"fishes":
a) There are a lot fishes in the sea.许多种类>的小鱼.
b) Ichthyology is the study of fishes.