The nouns school, college, bed, prison, jail are used without an article when they lose their concrete meaning and express the purpose for which the objects denoted by these nouns serve.
When these nouns denote concrete objects the articles are used according to the general principle.
#1. School, College
to be at school
to go to school } to be a schoolboy (schoolgirl)
to be at college — to be a student of a college
to leave school — to finish or drop one’s studies
School begins at five.
She went to College in the North. (Gow and D’Usseau)
His history since he left school had been indicated in the last page. (Thackeray)
It was at seventeen that he decided to leave school.
to go to the school — not as a pupil (the building is meant) to leave the school — to leave the building
Mother went to the school yesterday to attend a parents’ meeting. She left the school at 7 o’clock.
#2. Bed
| to go to bed | And now you had better go to bed. Good-night. (Voynich) |
| to be in bed
to be in the bed |
|
| to be on the bed (an article of furniture is meant) | Her portrait was on the wall beside the bed. (Voynich) |
#3. Prison, Jail
to be in prison (in jail) — to be a prisoner to be sent to prison
to be put in prison} as a prisoner
Mr. Dorrit was in prison many years. Mr. Dorrit was sent to prison for debt.
The last they had heard of him was that he was in jail for having killed a person in a fight. (Abrahams)
to be in the prison
to go to the prison} not a as prisoner (the building is meant)
Mr. Dorrit’s family lived in the prison.
The prison proper dated from 1822. (Dreiser)