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Questions 19 to 22 are based on the conversation you have just heard.
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Space is a dangerous place, not only because of meteors (流星) but also because of rays from the sun and other stars. The atmosphere again acts as our protective blanket on earth. Light gets through, and this is essential for plants to make the food which we eat. Heat, too, makes our environment endurable. Various kinds of rays come through the air from outer space, but enormous quantities of radiation from the sun are screened off. As soon as men leave the atmosphere they are exposed to this radiation but their spacesuits or the walls of their spacecraft, if they are inside, do prevent a lot of radiation damage. Radiation is the greatest known danger to explorers in space. The unit of radiation is called "rem". Scientists have reason to think that a man can put up with far more radiation than 0.1 rein without being damaged; the figure of 60 rems has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damage—a person may feel perfectly well, but the cells of his or her sex organs may be damaged, and this will not be discovered until the birth of deformed children or even grandchildren. Missions of the Apollo flights have had to cross belts of high amount of rems. So far, no dangerous amounts of radiation have been reported, but the Apollo missions have been quite short. We simply do not know yet how men are going to get on when they spend weeks and months outside the protection of the atmosphere, working in a space laboratory. Drugs might help to decrease the damage done by radiation, but no really effective ones have been found so far. The best title for this passage would he ______.
Space is a dangerous place, not only because of meteors (流星) but also because of rays from the sun and other stars. The atmosphere again acts as our protective blanket on earth. Light gets through, and this is essential for plants to make the food which we eat. Heat, too, makes our environment endurable. Various kinds of rays come through the air from outer space, but enormous quantities of radiation from the sun are screened off. As soon as men leave the atmosphere they are exposed to this radiation but their spacesuits or the walls of their spacecraft, if they are inside, do prevent a lot of radiation damage. Radiation is the greatest known danger to explorers in space. The unit of radiation is called "rem". Scientists have reason to think that a man can put up with far more radiation than 0.1 rein without being damaged; the figure of 60 rems has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damage—a person may feel perfectly well, but the cells of his or her sex organs may be damaged, and this will not be discovered until the birth of deformed children or even grandchildren. Missions of the Apollo flights have had to cross belts of high amount of rems. So far, no dangerous amounts of radiation have been reported, but the Apollo missions have been quite short. We simply do not know yet how men are going to get on when they spend weeks and months outside the protection of the atmosphere, working in a space laboratory. Drugs might help to decrease the damage done by radiation, but no really effective ones have been found so far. The harm radiation has done to the Apollo crew members ______.
Passage One Questions 26 to 29 are based on the passage you have just heard.
Selling Expertise on the Internet for Extra Cash Teresa Estes, a licensed mental-health counselor, watched as business at her private practice decreased last year. Then the single mother turned to her keyboard to boost her income. Ms. Estes applied to become an "expert" on Live Person Inc., a Web site where clients pay for online chat time with professionals and advisers of all fields. For $1.89 a minute—a rate she set—Estes dispenses advice to clients around the globe. She spends about four hours a day online, often at night, when her daughter has gone to bed. "It was the economy," she says of her move to take her skills online. "Live Person is more profitable than my private practice." Ms. Estes had charged her private clients up to $75 an hour. As the recession deepens, a small but growing number of people are taking their skills online, offering expertise or performing specified tasks for a fee. Labor-at-the-keyboard sites are gaining popularity as people increasingly turn to the Web in search of work. Internet job-search sites saw a 51% rise in traffic from January 2008 to January 2009, according to comScore Media Metrix, to 26.7 million unique visitors. Among the many fee-for-service Web sites out there, at least three arc attracting a significant number of users—though consumers should exercise a healthy degree of skepticism when consulting any of these sites. Live Person seeks out experts on a slew of topics, including mental health, financial services, shopping and fashion, as well as psychics and spiritual advisers. Mechanical Turk, a Web service run by Amazon. coin Inc., pays workers to perform tasks, such as cataloging products online. Associated Content pays contributors to write articles on a wide range of subjects, from organic flower gardening to how to apply for financial aid. Live Person went public in 2001 , and the current version of the site was launched in late 2007. Today, the site has 30,000 registered experts, attracting an average of 100,000 people a year who pay for the offered services, says Chief Executive Officer Robert LoCascio. Roughly 3,500 people have made contributing to the site their full-time job, he says. Live Person says it vets contributors’ qualifications, such as medical licenses or financial certification, through a third party, and relies heavily on its community reviews. Some 200 people a day apply to he Live Person experts, up from 120 a year ago, says Mr. LoCascio. Once cleared, advisers work with clients on a cost-per-minute basis set by the adviser. The site takes a commission of between 30% and 35%. Associated Content, by contrast, reviews submissions in house and then decides how much to pay for them. The site, which specializes in how-to pieces and feature stories on news topics, had 237,000 registered contributors and more than one million content pieces as of February, both about double from the same mouth a year ago. After posting the content, the site sells advertisements against it and distributes it to other companies, such as online shoe retailer Zappos, which use the content on their own Web sites. If Associated Content accepts a submission (it says it rejects about 25% of them) , the author gets between $5 and $30, plus $1.50 for each 1,000 page views. An ability to write "search-engine-optimized" content, an industry term for generating good Google results, helps, says site founder Luke Beatty. People are not only looking for payment but also establishing their credentials "as somebody with experience", he says. Writing about a specific profession, such as law or real estate, helps raise a person’s profile online, enhancing his job searches, says Mr. Beatty. Sabah Karimi, a 26-year-old from Orlando, Fla., left a career in marketing to become a full-time freelance writer and now spends between 8 and 10 hours a week writing for Associated Content. She has been at it for about three years and says she earns roughly $1,000 a month from her past and current submissions. Ms. Karimi cautions newcomers to Associated Content that it takes time to build up earnings. She says she learned how to write articles that would bring traffic and often looks for newsy ideas that will attract readers. Mechanical Turk, by contrast, is based on "crowd sourcing", or breaking a task into lots of tiny pieces and giving it to a big group of people to complete quickly. Most of these jobs—which the site calls HITs, for human intelligence tasks—pay just a few cents. Efficient MTurkers, as they call themselves, can make more than $100 a week doing things such as finding someone’s email address or labeling images of a particular animal in a photograph. Amazon says that MTurk now has 200,000 workers from 100 different countries, but it doesn’t keep track of past figures. The site—named for an 18th-century stunt involving a turbaned chess-playing "machine" with an actual chess master hidden within—began as a way to help Amazon manage its product database. Amazon uses the site to help sort images and content, paying people a few cents a task. Mechanical Turk also serves a variety of companies who need Web tasks performed, especially those that require a human element. Knewton Inc., for example, uses it extensively for focus-group-type tasks, as well as enlisting people to take its practice tests. Keri Knutson, a mother of five, discovered Mechanical Turk when her eldest son was headed for college. Ms. Knutson, now 45, needed money for his tuition and fees. She took on all kinds of low-paying but easy tasks at the beginning, from finding a place to purchase a specific item to identifying the name of a street in a photograph. People looking to make money online as fee-afor-service experts should read the fine print. Live Person has one of the more formal payment systems, requiring users to sign up for an account before talking with an expert. Some sites, including Associated Content and Mechanical Turk, reserve the right to refuse payment if a task is not completed satisfactorily. Most sites have a robust community of workers who regularly offer one another tips on which tasks pay the best. Mechanical Turk users have an independent site called Turker Nation (turkers. proboards80, com), which reviews the companies that solicit (索求) and pay for tasks so that workers can check a company’s record before taking on a task. Consumers who use these sites also need to exercise caution. Relying on legal or medical advice from an unknown online source has obvious drawbacks, and the Web sites acknowledge that some users have registered complaints about the advice offered on the sites. Live Person warns consumers to offer their financial and personal details with care. For the workers on these sites, even incremental sources of income are helpful these days. Ms. Knutson now spends the majority of her time transcribing Web audio and video for clients, earning about $250 a week for 30 hours of work. She says she has seen more competition lately but is determined to keep up her weekly pace. "If I didn’t have this money," she says, "we’d be struggling to find what to eat every week.\ What does Turker Nation do
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