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Article: What will power your house in the future? Nuclear, wind, or solar power? According to scientists at the Massachusetts Institute of Technology (MIT) in the US, it might be leaves -- but artificial ones. Natural leaves are able to change sunlight and water into energy. It is known as photosynthesis . Now researchers have found a way to imitate this seemingly simple process. The artificial leaf developed by Daniel Nocera and his colleagues at MIT can be seen as a special silicon chip with catalysts . Similar to natural leaves, it can split water into hydrogen and oxygen when put into a bucket of water. The hydrogen and oxygen gases are then stored in a fuel cell, which uses those two materials to produce electricity, located either on top of a house or beside the house. Though the leaf is only about the shape of a poker card, scientists claimed that it is promising to be an inexpensive source of electricity in developing countries. "One can imagine villages in India and Africa not long from now purchasing an affordable basic power system based on this technology," said Nocera at a conference of the American Chemical Society. The artificial leaf is not a new idea. The first artificial leaf was invented in 1997 but was too expensive and unstable for practical use. The new leaf, by contrast, is made of cheap materials, easy to use and highly stable. In laboratory studies, Nocera showed that an artificial leaf prototype could operate continuously for at least 45 hours without a drop in activity. The wonderful improvements come from Nocera's recent discovery of several powerful, new and inexpensive catalysts. These catalysts make the energy transformation inside the leaf more efficient with water and sunlight. Right now, the new leaf is about 10 times more efficient at carrying out photosynthesis than a natural one. Besides, the device can run in whatever water is available; that is, it doesn't need pure water. This is important for some countries that don't have access to pure water. With the goal to "make... Question: The purpose of the scientists at MIT in developing the new artificial leaf is to _ . Yes or no, is the answer "provide cheaper energy for developing countries"?
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Yes

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Article: It was late one evening. I can't remember what it was about, but my dad and I had a very big argument when my mom was away. We both said things we didn't mean, and in the end I said, "I'm leaving." And he said, "Good. The sooner, the better." I threw a few things in a suitcase and closed the door angrily behind me, not knowing where I was going. After walking aimlessly for about 20 minutes, I stopped at a local supermarket. Then my phone rang. It was my mom calling. She said, "Hey, Mary. Where are you? Dad is worried about you." "How can he worry about me? I've been away for nearly half an hour, but he didn't call," I said with annoyance . My anger returned and I remembered all the hateful things he'd shouted to me. "Listen, Mom. You can tell Dad that I'm fine. I'll call you tomorrow," I said and hung up. I walked around the store, trying to get my thoughts together. By the time I paid for my _ , it had been much later than I used to be out alone. When I left the supermarket, a large piece of white paper was in front of me. On the piece of white paper were these words: "Please come home! I miss you and I'm worried about you!" Then a car pulled up beside me. Hanging out of the window was my dad. Beside him, smiling gently, sat my mom. And that's when I started laughing. I laughed so hard that I cried. Despite my best efforts to run away from home, my father finally managed to track me down. I couldn't leave now, not with him sitting there with caring eyes. Question: What probably happened at the end of the story? Yes or no, is the answer "Mary returned home happily."?
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Yes

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Article: Have you ever had travel problems because your airplane was late? It is a common problem and it is getting worse. Airport delays make people angry and cost the country billions in lost work time. The Federal Aviation Administration (FAA) is the government agency that oversees air travel. They studied the problem of airline delays. They found eleven major problems and suggested eleven ways to fix them. Some of the problems are caused because different regions of the country do things differently. The regions don't talk to each other enough. Some of them need new computers. Also, more planes are flying. A strong economy has more people using airplanes to get around. Airplanes are a form of mass transportation now, like trains and buses were in the past. More planes in the airport cause delays. The airport in San Francisco is a good example. It is growing fast. Many people go through San Francisco to get to other places around the world. Ron Wilson of the San Francisco International Airport says, "If you've got 18 flights that all want to take off at 8:00 am and you're on the 18thplane in line, you're going to be 40 minutes late." Weather is another main reason for delays. Weather causes about 70% of delays. Fog or freezing rain can cause delays. The first thing the FAA wants to do is take control away from the regions during heavy traffic times and bad weather. A national center would make decisions on things that affect the whole country. The FAA also wants to put more distance between planes in the sky when the weather is bad. This rule could cause even more delays. The FAA knows that their solutions will not solve the problems with airport delays. But, they hope to make things better. There are just too many planes, too few traffic controllers, and not enough new technology. Question: Which of the following is NOT mentioned as a reason for airline delays? Yes or no, is the answer "A growing population."?
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No