یک

یک

"یک" means "one."

Here, 'یک' means 'a' or 'one', indicating a single book.

من یک کتاب خواندم.

I read a book.

In this sentence, 'یک' is used to signify that the person acted in a manner similar to 'a hero', adding emphasis on the example provided.

او مانند یک قهرمان رفتار کرد.

They acted like a hero.

'یک' here emphasizes 'a good day', as one single day that's characterized as good.

داشتن یک روز خوب اهمیت زیادی دارد.

Having a good day is very important.