Unix forms the basis of many operating systems.

He was an eyewitness to the incident.

A new approach is needed to solve this perpetual problem.

Alex is my best friend.

Japan's administrative divisions are divided into prefectures and municipalities.

He is reading a book about historical northern Korea.

My guinea pig is very cute.

The freight train passed through the station.

The mischievous child messed up the neighborhood flower bed.

He seemed to be angry about something and had a sulky look on his face.