A or the?

teacherJapan a/the urge

'a' is not possible. But 'the' sounds a bit more natural to me anyway.

teacherJapanHow can I tell when to use "a" or "the?" in cases like this in general?

The modification following (here, 'to go somewhere faraway...') often makes the noun quite definite in the speaker's or listener's mind.

I appreciate your quick reply:) I see! It's just a coincidence, but I'm now reading this book called 'Before I go to sleep,' and I've just come across the line, "I had an urge to let her see my journal, to let her read it all for yourself, but of course, I couldn't." Maybe that's why I got confused. I wonder why she (the woman, one of the characters in this book) used "a" instead of "a."

Sorry, "a" instead of "the."

teacherJapan I wonder why she (the woman, one of the characters in this book) used "a" instead of "a."

The modification following did not make the noun quite definite in the writer's mind.

teacherJapanHow can I tell when to use "a" or "the?" in cases like this in general?

"the" is related to "which?"

If the speaker believes that the question "which?" can be answered, he uses "the".

Which urge? The urge to go somewhere ...

OR, conceptualized differently:

Which

Thank you both very much for your answers. Oh, so in a way, I'd have to put myself in the writer's shoes to know the difference.

We don't have "the" or "a" in the Japanese language, which makes it much more difficult for me to grasp the idea of such differences, which I am sure comes naturally to you guys. Now I am quite into reading, so if I keep doing what I am doing, I might be abl