Some nouns refer to groups of people, animals or things:
My family is very dear to me.
I have a large family. They are very dear to me. = The members of my family …
The government is very unpopular.
The government are always changing their minds.
Sometimes we think of the group as a single thing:
The audience always enjoys the show.
The group consists of two men and three women.
Sometimes we think of the group as several individuals:
The audience clapped their hands.
The largest group are the boys.
The names of many organisations and teams are also group nouns, but they are usually plural in spoken English:
Barcelona are winning 2–0.
The United Oil Company are putting prices up by 12 per cent.
and the police is always plural:
The police are offering a £5,000 reward.