Why are Runa's parents feeling worried? (Understanding)

There are four persons mentioned in the text.

Runa's mother is a nurse and her father is a book-seller. They are worried because they are very busy with their work and cannot always take proper care of Runa and Rana during their exam time.

The family members support each other by sharing responsibilities. Rana helps Runa with her lessons and also helps his father in the book shop. Runa helps her mother with cooking and studies regularly to get a good result. This teamwork makes the family strong and happy.

Rana helps his father in the book shop.

Runa's mother is a nurse and her father is a bookseller. So they are very busy in their duties.

Runa will take part in Primary Education Completion Examination and Rana will take part in the Junior School Certificate Examination. So they are to studying hard.