Air pollution is a leading cause of cancer and classified among Group 1,or top, human carcinogens , said the International Agency for Research on Cancer (IARC), which is the World Health Organization's (WHO) cancer agency, on Oct 17,2013. The most widely used system for classifying carcinogens comes from the IARC, which places them into five groups. Group 1 carcinogens definitely cause cancer in humans. Group 2A is probably carcinogenic to humans, Group 2B is possibly carcinogenic, the carcinogenicity of Group 3 in humans is unclassifiable, and Group 4 is probably not carcinogenic to humans. Only a little more than 100 are classified as Group 1 cancer-causing substances, including ultraviolet radiation and tobacco smoke. "Our task was to evaluate the air everyone breathes rather than focus on specific air pollutants," the lARC's Dana Loomis said in a statement. "The results from the reviewed studies point in the same direction: the risk of developing lung cancer is significantly increased in people exposed to air pollution." In 2010, lung cancer resulting from air pollution killed 223,000 people worldwide, and there was also convincing evidence that it increases the risk of bladder cancer, according to the IARC. Air pollution is already known to raise risks for a wide range of illnesses, including respiratory and heart diseases. Air pollution is global, although the levels of it vary over space and time. Loomis said people in Asia, eastern North America, some places in Central America and Mexico, as well as North Africa have relatively high exposure. Developing countries with large populations and booming manufacturing sectors, such as China, are particularly at risk. Many cities in China, such as Beijing, frequently see smog. This week, Harbin, the capital city of Heilongjiang province, became the first Chinese city to officially suspend classes due to serious smog Many developed countries face similar problems, although to a lesser degree than most developing nations. In Europe, levels of many pollutants... Why should the international community take action without further delay? A) The composition and levels of air pollution vary from place to place. B) More and more people in developing countries are exposed to air pollution. C) Developed countries face air pollution, the level of which is higher than the safety limits. D) A large number of people worldwide are exposed to air pollution.
D
Since the 1970s, scientists have been searching for ways to link the brain with computers.Brain-computer interface(BCI) technology could help people with disabilities send commands to machines. Recently, two researchers, Jose Millan and Michele Tavella from the Federal Polytechnic School in Lausanne, Switzerland, demonstrated a small robotic wheelchair directed by a person's thoughts. In the laboratory, Tavella operated the wheelchair just by thinking about moving his left or right hand.He could even talk as he watched the vehicle and guided it with his thoughts. "Our brain has billions of nerve cells.These send signals through the spinal cord to the muscles to give us the ability to move.But spinal cord injuries or other conditions can prevent these weak electrical signals from reaching the muscles," Tavella says."Our system allows disabled people to communicate with external world and also to control devices." The researchers designed a special cap for the user.This head cover picks up the signals from the scalp and sends them to a computer.The computer interprets the signals and commands the motorized wheelchair. The wheelchair also has two cameras that identify objects in its path.They help the computer react to commands from the brain. Prof.Millan, the team leader, says scientists keep improving the computer software that interprets brain signals and turns them into simple commands."The practical possibilities that BCI technology offers to disabled people can be grouped in two categories: communication, and controlling devices.One example is this wheelchair." He says his team has set two goals.One is testing with real patients, so as to prove that this is a technology they can benefit from.And the other is to guarantee that they can use the technology over long periods of time. How did Tavella operate the wheelchair in the laboratory? A) By controlling his muscles. B) By talking to the machine. C) By moving his hand. D) By using his mind.
D
Q: When you are talking to somebody at a party, do you focus entirely on the person you are speaking with or does your attention keep jumping around the room to all the other people there? General1y, if the person is someone you really want to talk to, you will focus on him. Most other people will only get about half of your attention. You may think that this is OK, because if you don't really want to talk to him, then what does it matter if you don't give him your full attention? Consider two things. First, you may just not realize the importance of that conversation. If you are at a networking meeting and you hope to meet the CEO of Company X, but you end up talking to someone who has a low-level job at a different company, then you may let your attention wander as you speak to him. But maybe you don't realize that this person has already met the CEO and could introduce you. Do you think he will do that if he feels you don't really care about speaking to him? This doesn't mean you need to spend the whole time talking to him. Five or ten minutes of real attentive conversation can be worth 30 minutes to an hour of partial attention. Second, whether you want to speak to someone is based on the situation. You can love your wife, but if she tries to talk to you while you are watching something you like on TV, where is your attention going? Make your own decision, but if you want her to feel valued, give her your 100% attention. The nice thing is that in many cases you can give her your attention for a few minutes and then return to what you were doing. You miss very little, she feels valued, and all is good. If your wife wants to talk to you when you are busy, you should _ . A) decide what to do according to the situation B) go on with what you are doing C) stop doing anything immediately D) finish what you are doing with her
A: A
(Question)
Last spring, members of Alaska's Troop 34, based in Fairbanks, trudged out into the snowy wilderness to take part in their state's Take a Kid Trapping program. In many parts of the state, beavers are pests and need to be controlled. The 10-to-12-year-old girls found out where beavers lived, set traps, and skinned the two animals they caught. The girls hope to catch ten more beavers so that the entire troop can make mittens and hats with the fur. They also want to cook beaver meat. Troop leaders and members say the Scouts are doing a good deed by helping control the state's beaver population. But animal-rights activists say trapping is cruel. They want the Girl Scouts to stop in their tracks. Beavers aren't only causing a problem in Alaska. Residents in Sampson County, N.C., have turned to a local committee to help them battle the growing beaver population there. County landowners are frustrated after the county spent more than $ 50,000 in eight years trying to reduce the beaver population through a government program. The joint state and federal program included paying money to trappers for every beaver carcass they trapped. Many local residents say that the program didn't work because there were too few trappers. That's why the county set up its own committee to investigate other ways to control the area's beaver population. The county will rely on its own beaver-trapping program. It has hired a trapper to set traps in various areas. The county will pay $10 for every beaver carcass. Why do many people say that beavers are a nuisance? For beavers to survive, they need lots of water. Water provides the large rodent with a place to hide from meat - eating animals. Beavers also store food underwater for the winter. When there's not enough water in a particular area, beavers get busy building dams. Beaver dams can cause major flooding and damage to the surrounding countryside as the animals cut down trees to use in their construction projects. Beavers build canals to transport heavy objects. What is Alaska's Troop 34? A) A team of the Boy Scouts. B) An army. C) A team of the Girl Scouts. D) A sports team.
(Answer)
C