This ship doctor is an indispensable presence to protect the health of passengers during long voyages.

All passengers safely disembarked from the airplane.

His existence enriches my life.

You can feel his presence.

He wants to improve his sailing skills.

We are planning to sail during the summer vacation.

Water is indispensable to human life.

Water is indispensable to human life.

He decided to watch the stars all night long.

He decided to keep watching the stars all night long.