At School and at the School

Compare school and the school:

Alison is ten years old. Every day she goes to
school. She's at school now. School
begins at 9 and finishes at 3.

When we say that a child is at school or goes to school, we are not necessarily thinking
of a particular school. We are thinking of
school as a general idea.

 Today Alison's mother wants to speak to her
daughter's teacher. So she has gone to the
school to see her. She's at the school now.
Alison's mother is not a pupil. She is not "at
school", she doesn't "go to school". But if she
wants to see Alison's teacher, she goes to the
school (= Alison's school, a particular school).

We use prison, hospital, university, and church in a similar way. We do not use the when we are thinking of the general idea of these places and what they are used for. Compare:

 

"You're going to prison" said a police officer

  

I went to the hospital to visit my grandfather

 

 

• Tim's brother is in prison for robbery. (He is a prisoner. We are not thinking of a particular prison)

•Mrs Jones goes to church every Sunday.

• Mrs Jones goes to church every Sunday.
(to a religious service)

• Tim had an accident last week.

• He was taken to hospital. He's still in hospital (as a patient)

 • Tim's went to the prison to visit his brother.
(He went as a visitor, not as a prisoner.)

• She's at the hospital now. (as a visitor)

• He went to the church to repair the roof. (not for a religious service)

• Excuse me, where is the university, please?(= the university buildings)

Note: with most other places, you need the. For example, the cinema, the bank, the station.

Bed, work, home

We say: "go to bed / be in bed" etc. (not "the bed"):

•  It's time to go to bed now.             
• This morning I had breakfast in bed

but

• I sat down on the bed. (a particular piece of furniture)

We say:

1. go to work / be at work / start work / finish work etc. (not "the work"):

•  Ann didn't go to work yesterday.     
• What time do you usually finish work?

2. go home / come home / arrive home / be at home etc.:

•  It's late. Let's go home.                         
• Will you be at home tomorrow afternoon?

3. We say "go to sea / be at sea" (without "the") when the meaning is "go/be on a voyage":
•  Keith is a seaman. He spends most of his life at sea.

but

• I'd like to live near the sea.                 
• It can be dangerous to swim in the sea.