Detailed Instructions: 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.
Problem:Sentence: Whatever their origins, their culture evolved under the pressure and influence of foreign forces.
Solution:
When is this evolution expected?