He practices every day to improve his sailing skills.

We plan to sail on a yacht during the summer vacation.

Studying the history of the Imperial Examination is important for understanding the past of our country.

Maintaining oral hygiene is very important for overall health.

He is working at the pithead.

Sexual intercourse is one of the basic human desires.

They were having sex in secret.

We should always remember the power of Kannon in difficult times.

I used an optical microscope for an experiment at school.

The saffron cod is a winter specialty in Hokkaido.