Teacher: 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.
Teacher: Now, understand the problem? If you are still confused, see the following example:
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 _ .
Reason: It is clearly mentioned in the article that to the check effect of mood on children is the main purpose of the experiment.

Now, solve this instance: Article: There are over one million superstitions , and most people believe at least one or two of them. Many people are superstitious about numbers. They think that there are lucky numbers and unlucky numbers. The number 13 is often considered unlucky. In some parts of the world, buildings have no 13th floor and streets have no houses with the number 13. In Japan, "4" is considered unlucky because in Japanese the word "four" is pronounced the same as the word "death" . Japanese never give gifts of four knives, four napkins, or four of anything. What are the lucky numbers? Seven is a lucky number in many places, and "8" is considered a lucky number in Japan and China. In China, businesses often open on August 8, and many couples register to get married at eight past eight on August 8. Superstitions about numbers are so widespread that some people--called numerologist--make a living by giving advice about numbers. In 1937, when the Toyoda family of Japan wanted to form a car company, they asked a numerologist if "Toyoda" would be a good name for the company. The numerologist said it would not be. He explained that "Toyota" would be a better name for the company. The family took his advice. As a result, millions of people drive "Toyota" and not "Toyoda" . There are many other kinds of superstitions. There are superstitions about eating, sleeping, sneezing and itching . There are superstitions about animals and holidays and horseshoes. There are even superstitions about superstitions. Those superstitions will tell people how to reverse bad luck. When the Japanese bump heads, they immediately bump heads again. According to a Japanese superstition, the first-bump means their parents will die, but the second bump "erases" the first bump To reverse bad luck in general, people turn around three times, turn their pockets inside out, or put their hats on backwards. In the United States, baseball players sometimes wear their caps backwards when their team is losing. It looks silly, but the baseball players do not mind if it helps them win the game.
Answer: causing great troubles both in Japan and in China
Student:
It can be inferred that superstitions about numbers are_.