fish一條魚可數還是不可數

　　There are about 30 000 species of fish in the world.

　　世界上約有3萬種魚。

　　Fishing is good at high water.

　　高水位有利于釣魚。

　　How can you tell what sex a fish is?

　　你怎樣辨別一條魚的雌雄？

　　I don't like fish.

　　我不喜歡魚。

　　You need a licence to fish in this river.

　　你在這條河里釣魚要有許可證。