Question

How do you know when to use “a” or “the” in a sentence? For example, “Are you riding a bus?” or “Are you riding the bus?”

Answer 1

Hint: Read the question and decipher what it wants to convey, now go through the
various possibilities and use the elimination method to see which one of the rules fits the context of the question.

Complete answer: Indefinite articles are only used for an object/person
when one doesn’t know which noun one is referring to out of multiple nouns. It is used for
conveying the random nature of an object through a sentence.

‘The’ is used as a definite article for a thing/person when the reader knows exactly which
noun one is referring to. It refers to the specific nature of the subject.

For the sake of convenience, let us consider the sentence in the question. “Are you riding a bus?” or “Are you riding the bus?”

These two sentences are not exactly correct, as there is a preposition missing. The phrase should be ‘in a/the bus’. There is a difference in how you would use the articles then. As we have previously established, the definite article is to show specificity. This means that the person would have used the article ‘the’ if they knew which bus the subject was in.

Another distinction is the use of prepositions. The preposition often eludes to the usage of a specific article. However, more context is needed to establish a clear answer. So, the main difference between the two articles is only the specificity of the noun.

If one wants to refer to one thing that is clearly contextual, then they will go for a definite noun. Definite nouns also refer to something that is well known. So, sometimes people use ‘the’ before proper nouns.

If one wants to refer to a thing that is common and not one of a kind, then they will go for an indefinite article. Indefinite articles are used to refer to easily available things and are used to refer to one thing of a group. These cannot be used before proper nouns.

Note: The way to write the answer is to convey it in sentence form. You need to state the clear distinction between the usage of ‘a’ and ‘the’.