单选题[此试题无题干]
单选题. Questions 5 to 7 are based on the news report you have just heard.5.
单选题《复合题被拆开情况》 Volumes have been written about technology’s ability to connect people. But burying one’s nose in a book has always been somewhat isolating—with its unspoken assertion that the reader does
单选题《复合题被拆开情况》 Telecommuters fall into two camps. Some sit on the sofa watching daytime soaps, pausing occasionally to check their cell phones. Most, however, do real work, undistracted by meetings and ta
单选题. Questions 22 to 25 are based on the passage you have just heard.7.
单选题. Questions 12 to 15 are based on the conversation you have just heard.5.
单选题. Traffic fumes render the scent of flowers barely recognizable to honeybees and could have a serious impact on their ability to find food, new research has found. Scientists discovered that reactive pollutants in diesel (柴油) destroyed key chemicals in the odour of oilseed flowers making them smell different to the bees. "Honeybees have a sensitive sense of smell and an exceptional ability to learn and memorize new odours," said Tracey Newman, a neuroscientist at the University of Southampton. "The effects of diesel fumes on flower scent could have serious detrimental effects on the number of honeybee colonies and pollination (授粉) activity." Three-quarters of the world's food crops rely on bees and other natural pollinators. "Pollinator services are crucial to humankind," said Newman. But, there have been serious declines in natural pollinators in recent decades. A combination of factors is blamed, including the huge loss of the flower-rich habitats that sustain bees, as well as disease, and the impact of agricultural insecticides. The revelation that traffic fumes could be adding to the problems is significant, said Guy Poppy, a professor and ecologist at Southampton, who also worked on the research. He said, "Diesel exhaust is not the root of the problem, but clearly, with all the other stressors, adding another one is likely to be detrimental to bee health." The study, published in the journal Scientific Reports, tested bees' ability in the laboratory to recognize the aroma of oilseed rape flowers. Bees were strapped down and taught to associate floral scents with food in the form of sugar solutions. Once the bees learned the connection they began sticking their tongues out in anticipation of food even if it was not offered—an indication that they recognized the smell. When the scent was presented without pollutants the bees recognized it 98%～99% of the time. But after the scent was mixed with levels of diesel exhaust matching those found at roadsides, the bees only recognized it 30% of the time.21. What is the influence of reactive pollutants in diesel? ______
单选题Cash is unlikely to go away soon.Coins and paper 26_____ remain the most popular ways to pay for things in most countries.But in the long term，cash appears to be in a 27_____ battle with electronic pa
单选题. Questions 22 to 25 are based on the passage you have just heard.1.
单选题. Questions 16 to 18 are based on the passage you have just heard.1.
单选题. Questions 5 to 7 will be based on the following news item.5.
单选题. Questions 22 to 25 are based on the passage you have just heard.7.
单选题. Questions 16 to 18 are based on the passage you have just heard.1.
单选题. Questions22 to 25 are based on the passage you have just heard.7.