Learn Farsi: او بدون کتاب وارد دبیرستان شد. - He entered the high school without a book.

It uses the location suffix ـستان (-estan), meaning place of or land of (as seen in country names like Tajikistan). It attaches to the noun دبیر (dabir), which means teacher (and historically secretary or writer). So دبیرستان literally translates to place of teachers, which is the standard Farsi word for high school.

Why is there no preposition like به (to or into) used before the destination with the verb وارد شدن (to enter)?

Instead of using a separate preposition, the compound verb وارد شدن typically uses the ezafe to connect to its destination. The first part of the verb, وارد (entering), takes an ezafe linking it directly to the location: واردِ دبیرستان (vared-e dabirestan). You simply say he became entering-of the high school.

Why is there no را after دبیرستان if it translates to a specific, definite noun (the high school)?

The marker را is only used for specific direct objects. In this sentence, دبیرستان is the destination or complement of the compound verb وارد شدن. Because it's linked by an ezafe rather than acting as a direct object, را is grammatically incorrect here, even though English uses the definite article the.

The pronunciation is bedun-e ketab. Why is there an ezafe after بدون (without)?