高一英语限时阅读训练(一)AWith petroleum reserve（石油储量）decreasing, the search is on to replace gas with a cleaner, greener alternative．Though much eco-talk has centered on biofuels from corn and soybeans, the biofuel that looks more likely lo replace petroleum comes from a most unlikely source: algae．Algae（藻类）, like corn, soybeans, and other crops, grow through photosynthesis（光合作用）and can be processed into fuel oil．However, they yield 30 times more energy than land crops such as soybeans, according to the U．S．Department of Energy．Many algae species also can grow in saltwater and polluted water—while corn and soy require, arable land and fresh water that will be in short supply as the world's population balloons．"If you replaced all the diesel（柴油）in the U．S． with soy biodiesel, it would take half the land mass of the U.S. to grow those soybeans," says Matt Caspari, chief executive of Aurora Biofuels, a Berkeley, Calif-based private firm that specializes in algae oil technology．On the other hand, the Energy Department says that if algae fuel replaced all the petroleum fuel in the United States, it would require l5,000 square miles, which is a few thousand miles larger that Maryland（12,407squaree miles）, the 42nd state in land area．Another bonus: Because algae can be grown just about anywhere in a closed space, they're being tested at several power plants across the nation as a carbon absorber．Smokestack emissions （烟囱排放物）can be pumped directly into the ponds, feeding the algae while keeping greenhouse gases out of the atmosphere．Although processing technology for algae fuel—also known as "oilgae" in some environmentalist circles —is improving, it's still years away from reaching your local gas pump． "it's just a question of cost, because no large-scale facilities have been built yet," Caspari says．56．The underlined word "yield" in Paragraph 2 can be replaced by "_______"． A．control B．give in C．grow D．produce57．Compared with corn and soybeans, algae_____． A．may pollute water and soil B．provide much less energy C．can grow in poor conditions D．need more special care58．According to Paragraph 3, one of the advantages of producing algae fuel is that ____． A．it can be used more widely B．it is more easy to produce C．it needs much less land D．it costs much less money59．What do we learn about algae from Paragraph 4? A．People can grow algae anywhere． B．Algae help protect the environment. C．Fish can get more oxygen from algae. D．Algae product less waste．BBirds that are half-asleep—with one brain hemisphere (半球) alert and the other sleeping—control which side of the brain remains awake, according to a new study of sleeping ducks. Earlier studies have documented half-brain sleep in a wide range of birds. The brain hemispheres take turns sinking into the sleep stage characterized by slow brain waves. The eye controlled by the sleeping hemisphere keeps shut, while the wakeful hemisphere’s eye stays open and alert. Birds also can sleep with both hemispheres resting at once. Decades of studies of bird groups led researchers to predict extra alertness in the end-of-the-row sleepers which tend to be attacked more easily. Sure enough, the end birds tended to watch carefully on the side away from their companions. Ducks in the inner spots showed no preference for gaze direction. Also, birds napping at the end of the line depend on single-hemisphere sleep, rather than total relaxation, more often than inner ducks did. Turning 16 birds through the positions in a four-duck row, the researchers found that compared with 12 percent for birds in internal spots, outer birds half-asleep during some 32 percent of napping time. “We believe this is the first evidence for an animal behaviorally controlling sleep and wakefulness at the same time in different regions of the brain,” the researchers say. The results provide the best evidence for a long-standing assumption that single-hemisphere sleep evolved as creatures scanned for enemies. The preference for opening an eye on the lookout side could be widespread, he predicts. He’s seen it in a pair of birds napping side-by-side in the zoo and in a single pet bird sleeping by a mirror. The mirror-side eye closed as if the reflection were a companion and the other eye stayed open. Useful as half-sleeping might be, it’s only been found in birds and such water animals as dolphins, whales, and seals. Perhaps keeping one side of the brain awake allows a sleeping animal to surface occasionally to avoid drowning. Studies of birds may offer unique insights into sleep. Jerome M. Siegel of the UCLA says he wonders if birds’ half-brain sleep “is just the tip of the iceberg.” He supposes that more examples may turn up when we take a closer look at other species.60. According to the passage, birds often half sleep because ______. A. their brain hemispheres take turns to rest B. they 。