单选题 Barter (易货贸易), the exchange of goods and services without the use of money, is not a new idea, but over the past decade, this type of transaction has been transformed into a sophisticated business practice. Today, the barter industry is composed of several thousand independent barter exchanges representing an estimated 100000 businesses worldwide turning over US $9 billion per annum. Through bartering, businesses in Asia, US, Australia and Europe have saved millions of dollars and were consistently able to move as much extra inventory (存货) as they want. But why is barter system back in style? There are many good reasons, but underlying them all is one fundamental business motivation: profit. Businesses can use barter to conserve cash, generate new business, and turn excess and idle inventory into useful products and services. Moreover, the rising inflation, job losses and the slowing economy have prompted an explosion of bartering where businesses as well as individuals can get what they want without spending any of their precious cash. The barter system enables traders to find new buyers of their products and services from the targeted universe of participants trading within a particular exchange. Barter exchanges are done by using a trade currency to measure the exchange of goods and services between businesses and individuals. Barter currency give people the ability to purchase a future good or service that equals the amount of barter currency they own. This method allows businesses as well as individuals to get the things they need without having to expend additional money. Instead, they can use the things they no longer need or want to get the things they do need. Bartering can also be used by businesses that are seasonal in nature such as resort hotels. A bartered hotel room is more cost effective than an empty one. Bartering thus allows businesses to capitalize on unproductive assets and spare capacity. With a large exchange, it is possible to barter pretty much anything. There are exchange markets and online auctions that allow businesses to sell or trade their inventory or to purchase items that they want such as: barterplant.com, a free online community for trading items, services, and knowledge; swaptree.com, which specializes in trading books, video games, DVDs, and music and swapstyle.com, which allows members to swap clothes, shoes, cosmetics, and accessories. Although cash still in control, barter industry experts think, there is more room for barter. They predict that the globalization of barter over the next decade will be powered by a universal barter currency. Having a barter currency, which does not go up and down depending on the stability or instability of the world markets, means that the future prospects of the barter industry look pretty bright.

单选题Advances in computers and data networks inspire visions of a future " information economy" in which everyone will have (1) to gigabytes of all kinds of information anywhere and anytime. (2) information has always been a (3) difficult commodity to deal with, and, in some ways, computers and high-speed networks make the problems of buying, (4) , and distributing information goods worse (5) better. The evolution of the Internet itself (6) serious problems. (7) the Internet has been privatized, several companies are (8) to provide the backbones that will carry traffic (9) local networks, but (10) business models for interconnection--who pays how much for each packet (11) , for example--have (12) to be developed. (13) interconnection standards are developed that make (14) cheap and easy to transmit information across independent networks, competition will (15) . If technical or economic (16) make interconnection difficult, (17) transmitting data across multiple networks is expensive or too slow, the (18) suppliers can offer a significant performance (19) ; they may be able to use this edge to drive out competitors and (20) the market.

单选题We may infer from the passage that ______.

单选题She couldn't pay the full amount she owed, so she ______ part of it to the next month.

单选题Concrete is probably used more widely than any other substance except water, yet it remains largely unappreciated. “Some people view the 20th century as the atomic age, the space age, the computer age — but an argument can be made that it was the concrete age,” says cement specialist Hendrik Van Oss. “It’s a miracle material.” Indeed, more than a ton of concrete is produced each year for every man, woman and child on Earth. Yet concrete is generally ignored outside the engineering world, a victim of its own ubiquity and the industry’s conservative pace of development. Now, thanks to environmental pressures and entrepreneurial innovation, a new generation of concretes is emerging. This high-tech assortment of concrete confections promises to be stronger, lighter, and more environmentally friendly than ever before. Concrete is also a climate-change villain. It is made by mixing water with an aggregate, such as sand or gravel, and cement. Cement is usually made by heating limestone and clay to over 2,500 degrees F. The resulting chemical reaction, along with fuel burned to heat the kiln, produces between 7% and 10% of global carbon-dioxide emissions. “When we have to repeatedly regenerate these materials because they’re not durable, we release more emissions,” says Victor Li who has created a concrete suffused by synthetic fibers that make it stronger, more durable, and able to bend like a metal. Li’s creation does not require reinforcement, a property shared by other concretes that use chemical additives. Using less water makes concrete stronger, but until the development of plasticizers, it also made concrete sticky, dry, and hard to handle, says Christian Meyer, a civil engineering professor at Columbia University. Making stronger concretes, says Li, allows less to be used, reducing waste and giving architects more freedom. “You can have such futuristic designs if you don’t have to put rebar in there, or structural beams,” says Van Oss. A more directly “green” c6nerete has been developed by the Australian company TecEeo. They add magnesium to their cement, forming a porous concrete that actually scrubs carbon dioxide from the air. While experts agree that these new concrete will someday be widely used, the timetable is uncertain. Concrete companies are responsive to environmental concerns and are always looking to stretch the utility of their product, but the construction industry is slow to change. “When you start monkeying around with materials, the governing bodies, the building departments, are very cautious before they let you use an unproven material,” Meyer says. In the next few decades, says Van Oss, building codes will change, opening the way for innovative materials. But while new concretes may be stronger and more durable, they are also more expensive — and whether the tendency of developers and the public to focus on short-term rather than long-term costs will also change is another matter.

单选题A: Do you think that you can have these shirts finished by Friday morning? B: __________________ A. Sorry, we haven't finished yet. B. Why do you need them so early? C. I'm sorry. I couldn't possibly get them done by then. Saturday afternoon would be the earliest that you could have them. D. Don't you see we're short-handed?

单选题The police have asked for the ______of the public in tracing the whereabouts of the missing child.

单选题He came to inspect the house ___ buying it. A. in the event of B. with a view to C. in case of D. with regard to

单选题I had never seen so many people with so many disabilities. I returned home, silently ______. thinking how fortunate we really were.

单选题Scientists have been struggling to find out the reason behind blushing （脸红）。Why would humans evolve（进化） a 21__________ that puts us at a social disadvantage by 22__________ us to reveal that we have c

单选题Which of the following is NOT included as source of humidity in this passage?

单选题He is not under arrest, _____ any restriction on him.

单选题 Likewise, soot and smoke from fire contain a multitude of carcinogens.

单选题While watching television, ______. A. the telephone rang B. we heard the telephone ring C. we heard the telephone rang D. the telephone was rung

单选题Polar explorers have to be extremely ______ to endure the climate and other hardships of various kinds.

单选题In order to keep track of the hacker, ______.

单选题What is the main purpose of this article?

单选题They ______ in spite of the extremely difficult conditions.

单选题When John said that he would invite us all to a banquet, I think he ______ generous. Dont believe him. A) was only B) was only being C) is only D) has only been

单选题I just met her______on the way home from the bookstore.