Как преобразовать из вопроса: "why did they call this creature the 'hobbit'? " в косвенный вопрос?

1) kate left   the cafe late yesterday.   (past simple)

а. had left

b. left   (past simple)

2) she finshed   reading at 9 pm last saturday.   (past simple)

finshed   (past simple)

had finished

3) nick had done all his homework before his parents came home (past perfect)

did

had done   (past perfect)

4) that morning she dressed, phoned   somebody and went out.   (past simple)

had dressed, had phoned

dressed, phoned   (past simple)

5) i knew him at once though i had met   him many years before (past perfect)

had met   (past perfect)

met

6) by the age of 10 i had joined   some sports club (past perfect)

had joined   (past perfect)

joined

7) he wasn`t hungry because i had just had   breakfast   (past perfect)

just had

had just had   (past perfect)

8) they had finished   painting the room by 6 pm   (past perfect)

finished

had finished   (past perfect)

9) bob tried to find a job after he had served   a year sentence   (past perfect)

served

had served   (past perfect)

10) she painted her hair blonde and she looked very nice   (past simple)

painted   (past simple)

had painted