题目内容
Crops grow best ________ there is a lot of sunshine and water.
- A.that
- B.there
- C.unless
- D.where
名师点拨卷系列答案With 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 to replace petroleum comes from a most unlikely source: algae（藻类）.
Algae, like corn, soybeans, and other crops, grow via 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(适于耕种的) 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 only l5, 000 square miles, which is a few thousand miles larger than Maryland (12,407 squaree miles), the 42nd state in land area.
Another advantages: 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.
【小题1】The underlined word “yield” in Paragraph 2 can be replaced by “_______”.
| A．control | B．require | C．produce | D．grow |
nd soybeans, algae_____.| A．may pollute water and soil | B．can grow in poor conditions |
| C．provide much less energy | D．need more special care |
cording to Paragraph 3, one of the advantages of algae fuel is that ____.| A．it can be used more widely | B．it is easier to produce |
| C．it needs much less land | D．it costs much les s money |
| A．Environmental Protection | B．Biofuels from Corn and Soybeans |
| C．The False Hope of Biofuels | D．A Promising Oil Alternative |
“Eat local.” It’s one way to reduce human effect on the planet. Eating local means to try to buy and consume foods that are grown in places close to home. However, most of the food sold at supermarkets is not locally grown or produced. Trucks and planes deliver these foods from hundreds or thousands of miles away. During the transportation, greenhouse(温室)gases are produced, causing global warming. So the shorter the distance your foods must travel, the less the harm is done to the environment.
But how do you get local food if you live in a large city, hundreds of miles away from farms？Environmental health scientist Dickson Despommier and his students came up with the idea of a “vertical(垂直的)farm”. 
A vertical farm is a glass-walled structure that could be built as tall as a skyscraper(摩天大楼). Since the garden is built upwards, rather than outwards, it requires much less space than an ordinary farm. The world is quickly running out of room for ordinary farming. Vertical farms could be a key to this situation. Despommier imagines a 30-story building with a greenhouse on every floor. The walls of the building would be clear, to allow crops to get as much sunlight as possible. Depending on a city’s water resources, Despommier thinks hydroponic(水培的) farming is another method for the vertical farm which needs no soil to grow plants.
Despommier says the hydroponic greenhouses would use a system that would use a city’s waste water and fill it with nutritions to make the crops grow. If this method works, it would provide food to a city and save millions of tons of water.
The idea of a vertical farm has attracted the attention of government officials around the world. Scott Stringer, a government official from New York City, thinks the city is suitable for the vertical farming. “Obviously we don’t have much land left for us,” Stringer said. “But the sky is the limit in Manhattan. ”
Despommier admits that there is still a lot of work to do to make vertical farms a reality. “But I think vertical farming is an idea that can work in a big way,” he says.
【小题1】Why are people advised to eat local?
| A．Because it means convenience(方便) to people. |
| B．Because it can help people save a lot of money. |
| C．Because local food has more nutrition. |
| D．Because it is environmentally friendly. |
| A．It produces healthier food. |
| B．It does less harm to the cities. |
| C．It needs less space of the city. |
| D．It requires less transport costs. |
| A．people can make full use of vertical space of Manhattan |
| B．there is a limit for using empty land in Manhattan |
| C．the height of buildings in Manhattan is limited |
| D．Manhattan can spread as far as possible |
| A．No soil is needed to grow plants in a vertical farm. |
| B．It has solved the problem of the food shortage in a big way. |
| C．It is a 30-story building with a greenhouse on every floor. |
| D．Crops are mainly grown in the rainwater in a vertical farm. |