Do you understand the necessity of this project?

That information is unnecessary.

That information is completely unnecessary.

Our school has introduced a new PA system.

He is an expert in systems engineering.

He thinks that war is a necessary evil.

The filesystem of my computer has broken down.

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

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

He studied abroad in America to receive higher education.