During rush hour, the trains are very crowded.

He is a perfectionist, but we must not forget that even monkeys fall from trees.

He always does perfect work, but he made a mistake today. Well, even monkeys fall from trees.

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.

My class starts at eleven o'clock.

I eat lunch at twelve o'clock.

Greenwich Mean Time is the standard that determines the time of the world.