He encountered the enemy on the battlefield.

He moved agilely to avoid the enemy bullets.

The enemy aircraft invaded our airspace.

We are ready to invade enemy territory.

We are conducting training to devise strategies against hypothetical enemies.

In physics class, I learned about the properties of convex mirrors.

This magic mirror came from China.

He attached a new reflector to his bicycle.

The speculum of this bird has a very beautiful color.

He was observing the stars with a telescope.