There are various ethnic groups in the world.

He is very interested in science.

I think it's important to get enough sleep.

In order to keep the secret, he said, 'One word too many will be the end of me,' and didn't say anything.

The water vole is a small mammal native to Europe.

The European water vole is a small mammal native to Europe.

Due to his somnambulism, he may walk around unconsciously in the middle of the night.

My mother does tough scrubbing and washing every day.

He is an expert in folklore studies, and his research is highly regarded worldwide.

Democracy should give everyone the right to express their opinions equally.