‘a’ with ‘composure’ is equal to ‘a’ with ‘a’.
In English, the word “composure” is an uncountable adjective. Can you suggest me a sentence like this
- for a kid that has very little self-esteem?
- He withstood all that with a composure and a steadiness that astonished us all.
- She has a calm vigilance bordering on serenity.
- What teach us about the importance of balance after a difficult relationship.
- …until showing a composure that we hadn’t previously given him credit for.
- …and he handled this with composure uncommon to a fifteen-year-old.
Do the articles that have uncountable nouns come out of an indefinite article?
What is it like to win a first class job?
In these cases each “composure” represents a particular instance of composure. In your first sentence, the composure, the instance of it that astonished us all.
In all cases except number 4, the composure is qualified by a subordinate clause. Why we say ”’ and don’t call it an uncountable noun’? If a number is ambiguous to you, what is your number? In this case, the “a” implicitly refers to an instance of composure, but if I were the writer’s editor I would remove it.
This sort of thing happens a lot with uncountable nouns. I like water. Even
when I can’t drink water at all, there are some nice examples.
What is water from our wells?
I like eating fish. So it seems worth it.
What are some of the fun animals I catch into my lake?
Piano soundboards are made of spruce.
Piano Soundboards are made exclusively of the spruce that comes from Sitka, Alaska.
So, as soon as you qualify it, you are not talking about all of whatever uncountable thing you’re referencing. As soon as you’re not talking about all of it, it becomes countable.