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.

[Q]: Article: This is a dangerous world we live in.The number of murders goes up every year, people are dying of cancer, more people contract HIV, more teens are using drugs, etc.You know this because you have heard all the statistics on the news and in the paper. But do you really have an accurate idea what they mean? The numbers are growing up, but how do they compare to the growth in population? Are more cases of these diseases being reported because of better testing techniques, or are the diseases more common? The fact is that without knowing the background statistics mean very little. This growing trend of reporting only part of the information is becoming dangerous.For example, several years ago a high school student reported the dangers of the chemical known as dihydrogen monoxide.This chemical, found in most cancerous tumors , is often found in the blood of people drunk on alcohol, and causes complete physical and mental dependence for those who take the chemical even once.After reading his report, more than 75% of his Advanced Placement Chemistry class voted to forbid this dangerous chemical! Every one of the above statements is true, yet this chemical is necessary to all life on earth.The students made the mistake because they voted knowing only a few statements and statistics, rather than the chemical's full background. The point of this article is that one should be aware of what is and is not being said.When one finds a new fact or number, one should try to consider other important information before forming an opinion with only half-truths.Always remember that the author is trying to convince you of his or her own view, and will leave out information that is different to his view.For example, look again at the statistics that suggest skiing is safe.Only 32 people may die each year when skiing, while 897 die from lightning strikes, but which is really the most dangerous? If you think about it, you realize far fewer people go skiing each year than the number of people who are in danger of a lightning strike.When you think about it, skiing is more dangerous than you might at first think when looking at statistics.If we teenagers are to be left in this world, we had better be able to think critically, and form our own views, rather than be easily persuaded by another's.To be warned is to be prepared.
Answer: readers are not able to analyze so much information at once.
[A]: Relative information is often left out because _ .

[Q]: Article: April Fool's Day , was a day of laughing and jokes. This day is kept in many countries, not only in Britain and the USA. This is a day to play jokes and make people laugh. Nobody knows when was the beginning of this custom. Some people connect it with the end of winter and the return of spring which make people merry and ready to play jokes. In Scotland young people were sent for hen's teeth or bird's milk and everybody laughed when they could find such things. In the USA and Britain some people could place a sign on a person's back with the words "push me!" Children often tell a grown-up that his sock is torn or he has something black on his face, and then shout "April Fool!" There is also the old purse trick. A purse is left lying in the street, but when someone wants to take it, it is quickly pulled back by a string which the hidden joker holds in his hand. Or the purse may be filled with stones. Sometimes invitations are sent to people, asking them to come and visit somebody, but when they come they see that nobody expects them. Some people like to telephone to the zoo on the day and ask for Mr. Fish, Miss Fox or Mrs. Cat. All these jokes are very old but still they make people laugh.
Answer: Someone
[A]: _ knows when the custom of April Fool's Day started.

[Q]: Article: Sleep is like food for the brain. Enough sleep helps the body and the brain grow and develop. However,many Chinese do not sleep well,and many do not pay enough attention to sleep. The Chinese Medical Doctor Association released the 2013 China Sleep Quality Index on March 19 to mark World Sleep Day---March 21. According to the index,nearly a quarter of Chinese people don't sleep well.Half said that they feel tired after getting up and 15 percent people have trouble falling asleep. Ye Jingying,a sleep expert at Beijing Tongren hospital,says:"If people often wake up during the night,or always feel weak and tired in the day,they should pay attention to their sleep pattern." Many people play with their cell phones or i pads before sleeping.The report said that this is one of the main reasons for bad sleep.Other reasons include stress and bad moods. How to sleep well? Above all,get enough sleep.Seven to nine hours of sleep every night is perfect for an adult,and eight to nine hours is best for a teenager. Forming good sleep habits is important.The report suggested that people need to keep away from digital devices for at least an hour before sleep. The lights keep their brains excited for a long while.Other suggestions include:try to go to sleep and wake up at the same time every day,even on weekends and during holidays,and do the same relaxing things before bed each night,like listening to soft music.
Answer: March 21
[A]:
According to the passage,World Sleep Day falls on _ .