Groundwater pollution has become a serious environmental problem.

I saw various aquatic creatures at the aquarium.

He is known as an expert in subcritical nuclear experiments.

The anterior scalene muscle is part of the neck muscles and plays a role in assisting with respiration.

He crossed many mountains and rivers to meet her.

Kujō Yoshitsune, the former Prime Minister and Regent of the Go-Kyogoku, played an important role in Japanese history.

Hoshoji Nyudo Zen Seki Hakutaijo Daijin is a courtesy title of Fujiwara no Tadamichi.

Please remember this old proverb, 'The friendship of a gentleman is insipid as water.'