Beautiful gives consonant sound.
Articles "A" and "AN" are used with some expressions.
For example:
Make a noise, give a warning, have a pain, have a great education etc.
A and An are used before one.
Do you have the book ? that he gave you?
Usually no article required before trouble.
She was in trouble وہ پریشان تھی
The officer went to the college to meet the professor.
Same purpose: no article
Different purpose: Article is used
We use article A for consonant sounds.
Because gift gives consonant sound.
She bought a gift.
She was a teacher.
وہ ایک ٹیچر تھی۔
Generally Article is used before occupations.
Give me an onion please!
مجھے ایک پیاز دیں پلیز
Usually A is used before a comparative degree of adjective.