Given the task definition, example input & output, solve the new input case.
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.
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
Output: Researchers did experiments on kids in order to find out _ .
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 case for you: Article: Abby Subark is a mother of two from Boston. "For my kids, I'm nervous. I don't know if they'll be able to achieve their American dream." She may be right. More than hard work or education, the best way to get rich in America is to be born rich. It is the case that somebody who is in the upper third of income, poor scores, in the bottom on tests when they are in eighth grade, is more likely to go to college and finish college than a poor kid with the top scores. That's what the working persons' children are up against. The Economic Policy Institute finds it would take a poor couple with 2 children 9 or 10 generations to achieve middle class status. That's about 200 years. The hallmark of American opportunity has always been the ability to do better than your parents. But compared with similar developed countries, the United States ranks fifth out of six for so-called intergenerational mobility . If you look at the mechanisms for upward mobility that were so readily available 50 years ago, they are becoming out of reach, like plentiful factory jobs with good wages and affordable education and health care. White families are twice as likely as blacks to be upwardly mobile. For most people in America today, _ If you started in the middle-income class, about 40 to 45 percent of what you are making right now is due to the fact that your parents were in the middle-income class. The rest is up to you. But for the millions of people who find themselves below the poverty line and the millions more who are the working poor, their starting point for the American dream leaves them painfully far away from the middle class.
Answer: Upward mobility in America is never easy.
Output:
The main idea of the passage is _ .