1 . Avi Loeb, a scientist, believes that we are not alone in the universe. The belief fits with Loeb’s alien (外星的) spaceship theory that at least one alien spaceship might be flying over the orbit (轨道) of Jupiter, which won the international attention last year.
Astronomers in Hawaii found the first known interstellar (星际的) object in late 2017. It was a bit of light moving so fast past the sun that it could only have come from another star. Almost every astronomer on the planet was trying to figure out how the object, called “Oumuamua” got to our far-away, part of the Milky way galaxy. “One possibility is that ‘Oumuamua’ is debris (碎片) from an advanced technological equipment,” Loeb said. “Technology comes from another solar system just showed up at our door.”
“‘Oumuamua’ is not an alien spaceship,” Paul Sutter, another scientist wrote. He suggested Loeb was seeking publicity. Most scientists think “Oumuamua” is some sort of rock. They think it could be an icy wandering comet.
Loeb says that “Oumuamua’s” behavior, means it can’t be a block of rock shaped like a long photo. He thinks it's more likely an object that’s very long and thin, perhaps like a long pancake or a ship’s sail. Loeb says that if someone shows him evidence that contradicts his beliefs, he will immediately give in.
Loeb believes himself a truth-teller and risk- taker in an age of very safe, too-quiet scientists. “The worst thing that can happen to me is that I would be relieved of my management duties, and that would give me even more time to focus on science,” Loeb says. He said he wouldn’t mind giving up all the titles he had and returning to the Israeli farming village where he grew up.
1. What does Loeb say about “Oumuamua”?| A．It is an icy comet. |
| B．It looks like a long photo. |
| C．It is actually some sort of rock. |
| D．It may come from another alien civilization. |
| A．Searches for. | B．Depends on. |
| C．Turns to. | D．Goes against. |
| A．He is foolish. |
| B．He is unsatisfied with his titles. |
| C．He is a firm believer in scientific truth. |
| D．He is uncertain about his career future. |
| A．Have Aliens Paid a Visit in Spaceships? |
| B．Do We Really Know about Space Theory? |
| C．Scientists Are Working on High Technology |
| D．Astronomers Are Encouraging Space Travel |
2 . Biofuels (生物燃料), gained from plants and animal matter, are a key solution to the environmental problems caused by fuels like coal. “Bioalcohol (生物酒精) is the most common biofuel and is produced by sugars found in materials such as corn. With some engine redesigned, it can be used directly by cars, buses, etc.,” says Professor Daniel Tan, “12 percent of transport fuel could come from biofuels, especially bioalcohol, by 2030.”
But a 2016 study of biofuels said, “Bioalcohol presently is mostly produced with food crops. Altogether, the environmentally-friendly biofuels rely on about 2-3 percent of the global water and land used for agriculture, which could feed a large number of hungry people.”
Energy experts have therefore been trying to deal with the problem. Recent research led by an international team found that the agave (龙舌兰) plant might offer a way out. This plant tends to be the right bioalcohol source to supersede others such as sugarcane (甘蔗) and corn.
Daniel Tan explains that the agave can be grown in unfavorable conditions and is not a major food crop. “It can grow in areas that lack water and rainfall without being watered by farmers, and it does not compete with food crops or put demands on limited water. This kind of useful plant is recently being grown in Australia. It can survive Australia's hot summers,” he says.
The study finds that sugarcane produces just a little more fuel per square meter each year than the agave. However, the agave outperforms sugarcane in a range of areas, including pollution to the earth, and water using. The agave uses 69 percent less water than sugarcane and 46 percent less water than corn for the same amount of fuel produced. As for corn，it produces less fuel per square meter each year than the agave.
However, Daniel Tan states: “The first generation of bioalcohol from the agave recently faces a big competition from oil, whose recent low price makes it far more attractive to customers. Without some policy support from the government, bioalcohol production from the agave faces big challenges.”
1. What can we learn about bioalcohol from the first paragraph?| A．It is popular among customers worldwide. |
| B．It is a kind of biofuel made from artificial matter. |
| C．It helps vehicles' engines stay in good condition. |
| D．It can play a big role in making transport fuel green. |
| A．Take the place of. | B．Take advantage of. |
| C．Get away from. | D．Get along with. |
| A．It improves the local weather. | B．It keeps the water in the ground. |
| C．It produces plenty of food for humans. | D．It puts low demands on growing environment. |
| A．Reduce the price of oil. | B．Make some favorable policies. |
| C．Expand agave bioalcohol's production. | D．Introduce competition into agave bioalcohol market. |
