You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.

Article: Homework can put you in a badmood , and that might actually be a good thing. Researchers from the University of Plymouth in England doubted whether mood might affect the way kids learn. To find out the answer, they did two experiments with children. The first experiment tested 30 kids. Someshapes were hidden inside a different, larger picture. The kids had to find the small shapes while sitting in a room with either cheerful or sad music playing in the background. To test their mood, the scientists asked the kids to point to one of five faces, from happy to sad. Children who listened to cheerful music tended to point to the smiley faces while the others pointed to the unhappy ones. The researchers found that sad kids took at least a second less to find the small shapes. They also found an average of three or four more shapes. In the second experiment, 61 children watched one of two scenes from a film. One scene was happy, and the other was sad. Just like in the first experiment, kids who saw the sad scene acted better compared to the others. The researchers guessed that feeling down makes people more likely to focus on a problem or difficult situation. Not all scientists agree with them, however. Other studies argued that maybe, that cheerful music in the first experiment distracted kids from finding shapes. While scientists work on finding out the answers, it still might be wise to choose when to do your tasks according to your mood. After eating a delicious ice cream, for example, write an essay.
Answer: whether mood affects their learning ability
Solution: Researchers did experiments on kids in order to find out _ .
Why? It is clearly mentioned in the article that to the check effect of mood on children is the main purpose of the experiment.

New input: Article: When the Japanese attacked America's ships at Pearl Harbor on 7 December 1941,they did it secretly.The makers of the movie Pearl Harbor have behaved differently. The noise about Pearl Harbor,made by Disney,has reached its highest point with its premiere before the movie opens in cinemas across the US at the start of the Memorial Day holiday weekend,a time to recall national heroes who sacrificed their lives on the battlefield. As Ben Affleck is the main star,the movie seems sure to become a success in the United States at least. At almost three hours in length,it promises to be a good old Hollywood movie.There is a love story.Affleck and his co-star,Josh Hartnett,both fall in love with the navy nurse,Kate Beckinsale and,of course,there is much human courage and love of country. It's certain that Disney will be accused of "changing" history.The showing of actual events in a movie always causes arguments. Bits of the story are deliberately not mentioned in the movie.It does not address the theory held by some historians that President Franklin Roosevelt knew about Japan's intention to attack the ships in Pearl Harbor.It is said he did nothing,as he was aware that such a blow would allow him to take America into the Second World War. Japan remains sensitive about being accused of wartime atrocities .And Disney is sensitive about its business in Japan,where it has a theme park. Not all the reviews of the movie have been full of praise.A reviewer for Newsweek,who was given an early preview,acknowledged that the 40-minute sequence showing the attack itself was powerful.The attack comes quite late in the movie,however,and the reviewer was less impressed with the characters and the love story. "Almost every line of the dialogue sounds like it comes from an old movie," the reviewer wrote.
Answer: a day when people celebrate the victories of World War II
Solution:
From the passage we can infer that the Memorial Day refers to _ .