单选题Though there are eight million blacks living in Europe, there is little debate about the ______of people of color, who have lived and worked here for generations yet rarely attain positions of power.

单选题Many______purchasers want personal real estate because homes reflect our social standing and financial success.

单选题The introduction of mass-production methods enabled many people______and gave them an unprecedented amount of mobility.

单选题Uncomfortable with their mean jokes, he tried to raise the tone of the conversation.

单选题______ of the twins was arrested, because I saw both at a party last night. A. None B. Both C. Neither D. All

单选题The tickets each ______ 10 dollars. A. cost B. costs C. is costing D. are costing

单选题Was it you or the wind______shut the door?

单选题The discovery that, fiction excluded, all bodies fall at the same rate is so simple to state and to grasp that there is a tendency to ______ its significance. A. underrate B. reassess C. praise D. eliminate

单选题American capitalism could not bear a holiday devoted only to gratitude—a notoriously hard concept to monetise. So after Thanksgiving comes Black Friday—and the country shops. China"s Singles" Day(named for all the ones in the date, 11/11)was for romance. That did not set registers ringing, either. Alibaba charged into the breach a few years ago with a Singles" Day sale. The results make the Americans cramming into Walmart look like timid socialists. This Singles" Day, the total volume of merchandise bought through Alibaba was Rmb57. 1 bn($ 9. 3bn), blowing past last year"s $ 5. 9bn. Total US retail sales for the entire four-day Thanksgiving weekend of 2013, online and in stores, were roughly $ 57bn. Alibaba, a marketplace operator rather than a retailer, takes up to 5 per cent of each transaction—no discount on Alibaba"s merchant fees for Singles" Day, thank you. So the day"s discounts of at least 50 per cent compresses revenues, especially considering that before the big day some sales are put off(one merchant has said that in the two weeks before Singles" Day its online sales drop 80 per cent). Alibaba has not disclosed the revenues it makes from Singles" Day. The big winners, other than consumers might be the delivery companies. Given all this, and that Alibaba"s $ 300bn market capitalisation is about 50 times net income, profitability matters. Alibaba"s shareholders will have to wait for the next earnings report for clues to whether Singles" Day 2014 was an economic success as well as a promotional one. Cash flow, in particular, bears watching. Capital expenditures tripled in Alibaba"s latest reported quarter, to $ 550m, as the company spent money on data centres, land rights and construction. Cash flow after capital spending therefore grew much more slowly than profit(even putting aside the $ 775m Alibaba tent to its merchants in the quarter). Chinese consumers are proving their buying power and Alibaba is proving its selling power. Earnings power will determine whether investors keep clicking buy, buy, buy.

单选题______what may, we're not going to make any concessions to his unreasonable demands.

单选题It is futile to try to destroy pests completely with chemical poisons, for as each new chemical pesticide is introduced, the insects gradually become______to it.

单选题Only A with early seventeenth century B observers did the music of C the original inhabitantsof the United States and Canada D entered recorded history.

单选题During the past few years archaeologist William Kelso delved into contemporary accounts of the settlement and searched for telltale postholes and palisades in the sandy soil.

单选题In the next few weeks consumer spending will increase by 7% in America, ______ with last year, according to a consumer survey by Deloitte, a consultancy.

单选题You'd rather not go to the picnic, ______ you?

单选题The attack is being seen as a deliberate attempt to______the peace talks.

单选题It would be a blessing for the human race if the mosquito could be eradicated.

单选题 Low-level slash-and-bum farming doesn't harm rainforest. On the contrary, it helps farmers and improves forest soils. This is the unorthodox view of a German soil scientist who has shown that burnt clearings in the Amazon, dating back more than 1,000 years, helped create patches of rich, fertile soil that farmers still benefit from today. Most rainforest soils are thin and poor because they lack minerals and because the heat and heavy rainfall destroy most organic matter in the soils within four years of it reaching the forest floor. This means topsoil contains few of the ingredients needed for long-term successful farming. But Bruno Glaser, a soil scientist of the University of Bayreuth, has studied unexpected patches of fertile soils in the central Amazon. These soils contain lots of organic matter. Glaser has shown that most of this fertile organic matter comes from " black carbon"—the organic particles from camp fires and charred wood left over from thousands of years of slash-and-bum farming." The soils, known as Terra Preta, contained up to 70 times more black carbon than the surrounding soil," says Glaser. Unburnt vegetation rots quickly, but black carbon persists in the soil for many centuries. Radiocarbon dating shows that the charred wood in Terra Preta soils is typically more than 1,000 years old. "Slash-and-burn farming can be good for soils provided it doesn't completely burn all the vegetation, and leaves behind charred wood," says Glaser. "It can be better than manure." Burning the forest just once can leave behind enough black carbon to keep the soil fertile for thousands of years. And rainforests easily regrow after small- scale clearing. Contrary to the conventional view that human activities damage the environment, Glaser says: "Black carbon combined with human wastes is responsible for the richness of Terra Preta soils." Terra Preta soils turn up in large patches all over the Amazon, where they are highly prized by farmers. All the patches fall within 500 square kilometers in the central Amazon. Glaser says the widespread presence of pottery confirms the soil's human origins. The findings add weight to the theory that large areas of the Amazon have recovered so well from past periods of agricultural use that the regrowth has been mistaken by generations of biologists for "virgin" forest. During the past decade, researchers have discovered hundreds of large earth works deep in the jungle. They are up to 20 meters high and cover up to a square kilometer. Glaser claims that these earth works, built between AD 400 and 1400, were at the heart of urban civilizations. Now it seems the richness of the Terra Preta soils may explain how such civilizations managed to feed themselves.

单选题He proved himself a ______ successor to the former Prime Minister.

单选题The decade of A the 1920" s was significant in Georgia"s history B because of the rapidity C withWhat agriculture D declined in the state.