Why are some nouns not preceded by articles?

There is no need to put an article before a noun in the following cases:

1) country names, usually without articles before people's names, such as England and Mary; ;

2) General plural nouns refer to a kind of people or things without articles;

They are teachers. They are teachers.

3) When abstract nouns represent general concepts, generally no articles are added;

Failure is the mother of success. Failure is the mother of success.

4) There is no article before the nouns indicating time such as season, month, festival, holiday, day and week;

We go to school from Monday to Friday. We have classes from Monday to Friday.

5) Don't put articles before nouns that address or represent official titles and positions;

Example: The guard brought the American to General Lee. The soldiers sent the American to General Lee.

6) No articles are added before the names of three meals, ball games and recreational sports, such as eating breakfast and playing chess.

7) When two or more nouns are used together, articles are often omitted;

I can't write without a pen or pencil. I can't write without a pen and pencil.

8) When by is used with trains and other means of transportation, there is no article in the middle, such as by bus and by train.

9) Individual nouns do not use articles; Individual nouns such as school, college, prison, market, hospital, bed, desk, class, town, church, court, etc. Directly after prepositions to express the deep meaning of nouns;

For example, going to the hospital is different from going to the hospital (not for medical treatment, but for other purposes).

10) ordinal number without article:

A. possessive pronouns before ordinal numbers

B. ordinal number as adverb;

He won the first place in the race.

C. In fixed phrases;

First, first, from beginning to end.