He belonged to the army.

She tends to be mentally unstable.

In physics, the gyroscopic motion is an important element in controlling the rotation of an object.

This mineral is called anhydrite.

Maintaining oral hygiene is very important for overall health.

He is working at the pithead.

We steered the ship towards the harbor entrance.

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.