TASK DEFINITION: In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.
PROBLEM: Article: When Juliet was a child, she often went to the city park and played with her friends. On a sunny morning, when Juliet came to the park with her mum, she looked around and felt very unhappy. "What's the matter, dear?" asked her mum. Juliet replied, "Mum, there's so much trash on the ground." Juliet's mum looked around. There was paper, boxes and glass bottles everywhere. "What can we do?" asked Juliet. "I'm sure you will think of something," said her mum. As soon as Juliet and her mum went home, Juliet painted a picture of the park and wrote a sign in large black letters at the top of the picture. The sign read "PLEASE KEEP OUR PARK CLEAN". Later, she took plenty of bags and went back to the park with her mum. Juliet put up her picture on a big trash can . "Will you help me pick up the trash, Mum?" Juliet said as she handed her mum a bag. "I sure will," replied her mum. The children at the park ran over to see what was going on. Juliet handed them each a bag. "Let's clean this place up," said Juliet. Then they began to pick up the trash, talking and laughing. Soon all the bags were full. "We need to come back another day. There's still some trash on the ground, but the park looks much better," said Juliet. Her mum said, "So it does. _ "
Answer: Because there was too much trash at the park.

SOLUTION: Why was Juliet sad?

PROBLEM: Article: Imagine life without the Internet -- not being able to chat with your friends or look up information for your homework or research project. That is the reality for nearly two-thirds of our world's population, either because they cannot afford WiFi access or are located in remote, inaccessible areas. Now Google has decided to do something about that. Google's Project Loon will attempt to send balloons high up into our earth's atmosphere in 2015. Each balloon will be equipped with a mini computer and a WiFi radio that will send Internet signals over the places it is floating over. The network equipment on Google balloons will communicate with a special antenna attached to each user's home. These antennae are in turn connected to a local Internet Service Provider. Each balloon will also communicate with each other to hand over signals as one floats out of an area, and another floats in. The balloons are 15 meters wide and made of a material that is three times thicker than the plastic bag at the supermarket. This helps them defend themselves against cold temperatures and changing air pressure. Google balloons will circle the earth at a height of 20 kilometers-- in a layer of our atmosphere known as the stratosphere . This is higher than the altitude at which planes fly. Once the balloons reach the desired altitude after being released from the earth, they will ride on air currents. What keeps these balloons from flying away? They will be controlled by people at the Project Loon command center. A pump operating on solar power will fill the balloon with gas to raise it or let gas out to lower it, based on instructions. This allows the balloon to float on different air currents which are moving either clockwise or anti-clockwise. There is no doubt that this technology can bring education to many children, weather information to farmers, and communication to natural disaster areas. However, one big question remains -- will some countries be comfortable with balloons above their heads? There could be concerns about spying and other problems.
Answer: Helping us learn more about the earth's atmosphere.

SOLUTION: What's the purpose of Google's Project Loon?

PROBLEM: Article: In a touching story, a family was shocked to find that a stranger had secretly paid for more than half of their Christmas gifts. When Ayers went to make a payment toward the $283 balance for her family's Christmas gifts at Walmart, her money was refused. According to a Walmart employee, a woman had paid a part of Ayers' bill after seeing her shopping in the store. The unknown woman also left Ayers a touching note, which left the mother of two in tears. Ayers, whose sons are 11 and 3, says the stranger's great generosity came at the perfect time for her family. Before the anonymous payment was made, Ayers had worried she would not be able to get her kids' toys in time for Christmas. Ayers is still looking for the woman who helped pay for their Christmas gifts for her kids. She took a picture of her receipt with the headline: This stranger paid 4 gifts for us. I wish I could thank her for helping give our kids a Merry Christmas! For thousands of families like Ayers', feeling this financial pressure around Christmastime is nothing new. These families who still have a roof over their heads and food on their tables often slip through the cracks -- they can afford all the necessities, but the "extras" are harder to come by. Considering that Americans are estimated to spend $882 on Christmas gifts this year, it makes sense that a family with a few financial problems would have a hard time filling the stockings for their kids. Realizing how common this Christmas problem really is makes Ayers' story even more special. These random acts of kindness around the holidays, often from nameless strangers, can determine what a family's Christmas looks like. Christmas may not be all about the material stuff, but for families, and especially for kids, it's the little things that can make the biggest difference.
Answer: The charismas gifts were free.

SOLUTION:
Why did the Walmart employee refuse Ayers' money?