He works as a captain of a submarine.

A nuclear submarine can travel underwater for a long time.

The submarine navigated carefully to avoid the underwater mines.

He always acts carefully.

He always tries to act with caution.

He practices every day to improve his sailing skills.

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

He always changes the topic to avoid the problem.

He always changes the topic to avoid the problem.

He loves diving and goes to the sea every weekend.