Here's why:
* Definiteness is implied: The context usually makes it clear whether a noun is definite or indefinite.
* Using "this" or "that": To emphasize definiteness, you can use "این" (in, "this") or "آن" (on, "that") depending on proximity.
* Using possessive pronouns: You can also use possessive pronouns like "my", "your", "his", "her", etc., to indicate definiteness.
Examples:
* English: The book is on the table.
* Farsi: کتاب روی میز است. (ketab rooye miz ast, "The book is on the table.")
* English: I want to buy a book.
* Farsi: میخواهم کتاب بخرم. (mikhaham ketab bekharm, "I want to buy a book.")
Let me know if you have other words or phrases you'd like to translate!