In this task, based on the given input, we ask you to write a question about when an event happened. Your question should be answerable with common knowledge on when events usually take place. For example, "going to school" usually happens during the day (not at 2 A.M). Don't create questions which have explicit mentions of answers in the text. Instead, it has to be implied from what is given. In other words, we want you to use "instinct" or "common sense". The written questions are not required to have a single correct answer.

Example input: Sentence: Jack played basketball after school, after which he was very tired.
Example output: When did Jack play basketball?
Example explanation: This event likely happened between 3PM to 8PM (definitely not 2AM). Therefore, this question is correct.
Q: Sentence: The fiction of Japanese imperial power had become infinitely extendable.
A:
When did the fiction of Japanese imperial power take root?