Question: When I was a seven-year-old girl, I used to go door-to-door with my mother to ask the residents for donations to the American Lung Association. Some would give a few coins; others, on rare occasions, a whole dollar; but most would silently shake their heads. No matter what the amount was, my mother always thanked the givers, wrote their names and addresses on her large envelope, and placed the money inside. And then we returned to our apartment, and my mother counted the money. The yield didn't match the effort: I don't think she collected more than $10. Still, she sent the collection to the organization. Even as a child, I knew my mother's actions were great, which aroused my pride in her. Asking poor people to give to an organization which aimed to help others wasn't what you did. Other charities gave to these folks; you didn't ask them to give. To them , her efforts likely seemed foolish. But to me, her efforts had an influence on me as I grew up. Although my charitable giving is modest, I faithfully and regularly donate to the organization which is aimed at fighting AIDS; to stop hunger, and homelessness; to support public broadcasting, the arts, and public education; and to heal families. And I volunteer my time to teach little girls and fix our badly broken public schools. I do these things because I believe I've been given much, so much is required of me. I never asked my mother why she collected those donations, and, besides, the lung cancer that killed her twenty-one years ago prevents me from asking now. But had I asked, my mother's response would have been simple:"Because I can."That's what she would have said. But from that look in her eyes and her daily efforts to make life a bit brighter, I know she also acted on hope that tomorrow would be better and that her actions somehow would make a difference. How did the author's mother influence her as she grew up? A) The author was busy doing something kind. B) The author learnt more from what her mother did C) The author knew how to fight against some diseases D) The author wondered why people should help each other
Answer: A

Question: If you look at the night sky, you'll often see stars moving very quickly. In fact, they move much more quickly than they should according to their size and the laws of physics. Scientists do not completely understand why the speed of these stars is so high. But many believe the reason is that much of the universe is made of something called "dark matter". Groups of stars called galaxies, such as the Milky Way, might even be made up of 90 percent dark matter. How much something weighs depends on where it is. The same object weighs only half as much on Mars as it does on Earth and almost three times as much on Jupiter. So scientists prefer to talk about the mass   of something rather than how much it weighs, because mass does not change. They can work out the mass of galaxies by measuring the distance between them and the speed they move at. Recently, Jorge Penarrubia, a senior academic at Edinburgh University, UK, and his team discovered something interesting: The mass of the Milky Way is only half as much as the mass of another nearby galaxy, Andromeda. This seems strange, and dark matter may explain why. Finding out more about dark matter could help us understand how the universe began, but this is not easy. Lots of scientists with different types of expert knowledge are working on the problem. We can't see dark matter, it's very difficult to measure and we can't find out its mass. Unlike stars, dark matter doesn't produce or reflect light. But we can make a good guess that it is there because of the way things move and the way light bends. Experts now think dark matter may be very different from the matter that we find on Earth. There may also be five times as much dark matter in the universe as ordinary matter. Dark matter is difficult to investigate because   _  . A) it travels at a very fast speed B) we can't see where it is or measure its mass C) it's hard to measure the light it produces and reflects D) it is much bigger than ordinary matter in size
Answer: B

Question: The United States is not part of the Kyoto Protocol.But since 2005 more than 1,000 mayors across the country have agreed to sign their own version of the protocol. It is called the United States Conference of Mayors' Climate Protection Agreement.Local leaders have agreed to follow the suggestions of the Kyoto Protocol in their communities.They have also agreed to urge state and federal governments to follow these suggestions.One goal is to reduce air pollution to the 1990 levels by 2012. A "green" city might work on several kinds of environmental goals and programs.These include air quality,reducing electricity use, green building, public health, the reuse of materials, water quality and clean transportation. The Natural Resources Defense Council works to protect the environment through action, law and science.One of its online projects is called Smarter Cities, which lists some cities that have made important environmental steps. Washington,D.C.is also a leading city for green roofs,with over 92,000 square meters of green rooftops.The city also launched a program called "Skip the Bag,Save the River."Stores charge people a fivecent  tax for using plastic or paper shopping bags instead of reusable bags.Money from the tax will be used to clean up a local river. New York City is using water as a renewable energy source.For several years, the city has experimented with water in the East River to create energy.Officials operating the program recently asked for permission to put into place 30 river turbine devices. The people of Portland, Oregon are among the top recyclers in the nation.People living there recycle over half of the waste they throw out.The city has also worked to provide green transportation by providing safe bike paths and free parking spaces where electric cars can get recharged. In Oakland, California, you can ride on one of several public hydrogenpowered  buses.These buses release zero pollution into the air.However,they cost about five times more than common buses. The United States Conference of Mayors' Climate Protection Agreement is aimed at  _  . A) reducing energy use B) reducing air pollution C) improving public health D) reusing waste materials
Answer:
B