instruction:
In this task, you're given an ambiguous question (which can be answered in more than one way). Your task is to write a question that clarifies the given question in such a way that the generated question has one unique answer.
question:
When did the voting age change from 21 to 18?
answer:
When did the debate begin to lower the voting age from 21 to 18?


question:
When was the return of the native written?
answer:
When was the return of the native started to be written?


question:
Length of new guardians of the galaxy movie?
answer:

What is the run time for Guardians of the Galaxy?