As the name suggests, an electric eel is a fish that can generate electricity.

The pelican eel is a rare fish that lives in the deep sea.

An electric eel can generate electricity.

European eels can live in both freshwater and seawater.

Grilled Japanese eel is one of the traditional dishes in Japan.

There are many lampreys living in this river.

The Paleogene period was a very important time in the history of the Earth.

I am planning to go to Inner Mongolia, an autonomous region of China, next week.

I have been to Outer Mongolia.

I have been to Chicago.