At that moment, he truly became the man of the hour.

In this chemical reaction, ammonium is produced.

In this chemical reaction, sodium plays an important role.

The atrium of this building is very spacious and bright.

He was caught by the police for jaywalking.

Hydra is one of the largest constellations in astronomy.

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.