In this task, we ask you to write a question that asks about "event duration", based on a given sentence. The question will likely start with "How long". Your question should be answerable based on the common knowledge of how long certain events usually last. 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". Note that the written questions are not required to have a single correct answer.

[Q]: Sentence: On London's Stock Exchange, Reuters shares rose five pence to 913 pence ($14.43).
[A]: How long is the stock exchange open?


[Q]: Sentence: After the second World Trade Center crash, Boston Center managers recognized that both aircraft were transcontinental 767 jetliners that had departed Logan Airport.
[A]: How long did it take Boston Center managers to recognize the jetliners?


[Q]: Sentence: they were heard saying when the photo was taken -- while Rowlf is clearly a selfie king.
[A]:
How long were they taking photos?


