This tree is very hard.

He is a person with a strong heart.

He finished the job in slightly more than an hour.

Tsuyoshi is my best friend.

He is a very strong person.

His strength comes from his mental power.

We should cherish our freedom.

There is not a single cloud in the sky.

The sky is very beautiful, isn't it?

Seeing the empty cup, he poured another cup of tea.