ایک

In a sentence

• مجھے ایک کتاب چاہیے۔

  I need one book.

  Here, 'ایک' is used as a numerical adjective to signify the quantity of one.

• یہ ایک دلچسپ کہانی ہے۔

  This is an interesting story.

  In this sentence, 'ایک' is used as an article similar to 'an' or 'a' to specify 'an interesting story'.

• ایک دن میں نے عجیب چیز دیکھی۔

  One day, I saw a strange thing.

  Here, 'ایک' functions as an adverbial phrase to indicate a nonspecific time, translating to 'one day' in English.