He is receiving treatment for obsessive-compulsive disorder.

The ship entered the port flying a quarantine flag.

I believe him.

There are many chambers in this castle.

They were conspiring.

There is a large fire wall in front of the fire department.

He was arrested for obstruction of public duties.

I can't find my Allen key.

Cell biology is the study of the structure and function of cells, which are the basic units of life.

He is a salary thief, contributing nothing to the company.