Most hotels in England are very expensive, (making a generalisation)
This is the most expensive hotel in town, (talking about a specific hotel)
Importance of context
The definite article refers to already mentioned items, and so its use depends
on context.
The Smiths had a son and a daughter. The son was in the Army and the daughter was training to be a doctor. On the Saturday, there was a terrible storm. Here,
the Saturday refers to a day in an area of time already mentioned.
On the Saturday of that week ... Jobs
Compare:
Tony is a builder. Tony was the builder of that house.
In measuring
Three times a week. Fifty kilometres an hour. £3.50 a kilo. £15,000 a year. Formally,
per can replace
a/an.
Unknown people
Use of
a/an emphasises that a person is unknown.
A Mr Jones called while you were out. Compare:
Matthew Smith is one of my favourite artists, (a person)
55
A Matthew Smith hangs in their bedroom, (a painting)
Some unique organisations do not use
the. Parliament, but
The (House of) Commons
Streets
Most streets do not use an article.
Green Road Godwin Street Exceptions are:
The High Street The Strand and street names without preceding adjectives. Compare:
Holly Drive The Drive
