He is known as an excellent system operator.

My older brother works as a systems engineer.

The astronomer conducted an observation of the night sky.

He likes to observe celestial bodies.

He is talking about something specialized that a commoner cannot understand.

It's difficult to guess his feelings.

He is an expert in systems engineering.

Our school has introduced a new PA system.

The filesystem of my computer has broken down.

He recognizes his success as being due to his heavy reliance on technology.