He is undergoing training for extravehicular activity.

He engaged in an extravehicular activity from the spaceship.

We crossed the sea by catamaran.

The shipworm is known for eating wood.

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

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.