The great auk is a species of bird that has become extinct.

Let's go watch a Superman movie.

He is strong like Superman.

I bought a new pencil sharpener.

The pH of this liquid is 7.

Hippocrates is called the father of medicine.

Scotland Yard is a famous police station in London.

Scotland Yard is the headquarters of the British police in London.

Sufism is a mystical branch of Islam.

The steward is conducting a safety check inside the aircraft.