واحدا

In a sentence

• أحتاج إلى واحدا فقط من هذه الأشياء.

  I need just one of these items.

  Here, 'واحدا' is used as a quantitative adjective describing the necessity of only one item out of many.

• لقد شاهدت واحدا من الأفلام الشهيرة البارحة.

  I watched one of the famous movies yesterday.

  In this sentence, 'واحدا' is used to specify one instance from a group of famous movies.

• يمكنك أن تختار واحدا مما يوجد على القائمة.

  You can choose one from what is on the menu.

  Here, 'واحدا' is utilized to indicate the act of selecting exactly one option from the menu.