What is the purpose of the が particle in this sentence?


友だちがきれいな花をくれました。

I have translated this as: Friend gave (me) beautiful flowers.

I did not understand the usage of が , couldn't we have used は ? And in this
case is my translation correct?




There are two possible reasons to use が instead of は here:

  1. This 友だち has not been mentioned in the discourse yet. In other words, this sentence is " **A** friend of mine game me a flower" rather than " **The** friend game me a flower."
  2. This _ga_ is a neutral-description _ga_. 
    * [Can someone explain me the use of は and が in this sentence?](https://japanese.stackexchange.com/q/43213/5010)
    * [Why is this sentence ungrammatical? 「お寺が公園のとなりです。」](https://japanese.stackexchange.com/q/68923/5010\])
    * [Why does 「電話は切れた」 sound more adversarial than 「電話が切れた」?](https://japanese.stackexchange.com/q/38639/5010)

Saying 友だちはきれいな花をくれました is still grammatical, but the meaning would be a little
different.




There are two possible reasons to use が instead of は here:

  1. This 友だち has not been mentioned in the discourse yet. In other words, this sentence is " **A** friend of mine game me a flower" rather than " **The** friend game me a flower."
  2. This _ga_ is a neutral-description _ga_. 
    * [Can someone explain me the use of は and が in this sentence?](https://japanese.stackexchange.com/q/43213/5010)
    * [Why is this sentence ungrammatical? 「お寺が公園のとなりです。」](https://japanese.stackexchange.com/q/68923/5010\])
    * [Why does 「電話は切れた」 sound more adversarial than 「電話が切れた」?](https://japanese.stackexchange.com/q/38639/5010)

Saying 友だちはきれいな花をくれました is still grammatical, but the meaning would be a little
different.

