That information is completely unnecessary.

He thinks that war is a necessary evil.

He is an expert in systems engineering.

Our school has introduced a new PA system.

The filesystem of my computer has broken down.

The automotive navigation system in my car has downloaded the latest map data.

Geographic Information Systems are very useful tools for map making and spatial data analysis.

We respect Japanese culture.

We are going on a trip tomorrow.

When I first met her, I introduced myself saying, 'I am Japanese.'