The traveller is looking at today's timetable while asking, and the timetable is still current. Transform the direct question 'When does the last bus leave?' into an embedded clause. Rewrite the exact fragment 'When does the last bus leave' in the blank: The traveller asked ___ .
Correct answer
when the last bus leaves
Explanation
The embedded clause drops does and restores present-tense marking to leaves after the subject. Retaining does or placing it before the subject would incorrectly preserve direct-question syntax.