This castle has existed for centuries.

We installed fire alarms to defend our house against fire.

He worked hard to accomplish his goals.

The security system detected a penetration.

The enemy's army invaded our country.

His role is the team leader.

There is a large moat around this castle.

The moat of the castle was deep, playing a role in preventing enemy invasions.

He dug a ditch in the garden.

His eyes are a deep blue.