English Language Learners Stack Exchange is a question and answer site for speakers of other languages learning English. It only takes a minute to sign up.
Sign up to join this community
I am really struggling to understand if I should use "a" or "one" in the below example. This is derived from another thread that became too confusing with the wrong examples. Thank you for any guidance.
The infection of a rodent causes the infection of all the other rodents in the world.
The infection of one rodent causes the infection of all the other rodents in the world.
In your example sentences I would suggest a little correction. You could do well to substitute "of" with "in". And the definite articles are mostly superfluous in your sentences.
In your sentences both "a" and "one" have the meaning "single". In that sense, both "a" and "one" are interchangeable, though "one" draws more attention to itself or what is being talked about.
In some instances "a" and "one" are not interchangeable. This is the case when "one" is used as a pronoun. e.g.
You are the one who made her cry. (Source)
There are other instances also. Kindly look at these pages,
https://duckduckgo.com/?t=ffab&q=difference+between+a+and+one&ia=web
My (Source) for the example sentence above.
From your question closed as a duplicate:
"The defence spending of [all / all the] countries increases if the defence spending of [one / a] country increases."
The defence spending of all countries increases if the defence spending of one country increases.
Correct. You do not have the context of a definite set, so you do not need (and must not use) the definite article.
The defence spending of all the countries increases if the defence spending of one country increases.
Incorrect. If you use the definite article, you need the context of a definite set. e.g.
In NATO, the defence spending of all the countries increases if the defence spending of one country increases.
I would suggest that "if the defence spending of a country increases" is wrong/unnatural, but I can't explain why. (And neither, it appears, can anyone else.) You can recast the sentence as: "If the defence spending of a country increases, the spending of its neighbours will follow suit", and this would be correct/natural.
The infection of one rodent causes the infection of all the other rodents in the world.
Quantity 1 rodent will spread infection to all other rodents in the world. The quantity is the focus.
The infection of a rodent causes the infection of all the other rodents in the world.
The quantity of rodents is not the focus, but rather the fact that X is a rodent versus being anything else.
You might say this if for some reason, you were talking about infection of animals in general and want to focus on rodents versus other animals.
