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I'm taking a test and have to guess the right answer to the question after the article. Article: Does it drive you crazy that your cell phone needs to be frequently charged for hours? A team of scientists led by professor Harold Kung at Northwestern University in the US may have solved your problem. They developed a lithium ion batery that holds 10 times as much power and charges 10 times more quickly than standard batteries, according to the BBC in a report on November 15. Lithium ion bateries are rechargeable and are widely used in cameras, smartphones and laptops. They charge through a chemical reaction in which lithium ions are sent between the two ends of a battery. How much power the battery holds and how fast it charges are limited by two things:how many lithium ions it has and how quickly these ions move. Current rechargeable batteries have an anode made of many carbon-based graphene sheets. To increase energy capacity, former experiments have tried to replace the carbon with silicon, which can hold far more lithium ions. However, this method did not work because the silicon was not stable enough. Kung's team managed to stabilize the silicon. They put clusters of silicon between the graphene sheets like a sandwich so that the silicon could not move around freely and take away the energy. The speed at which a battery charges is hindered by the shape of the graphene sheets because it takes a long time for the lithium to travel from one side of the sheet to the other.Sometimes a "traffic jam" occurs around the edges of the graphene. To solve this problem, Kung's team used a special chemical process to create tiny holes of 10 to 20 nanometers wide in the graphene sheets so the lithium ions would have a "shortcut" and be able to travel directly to the other side. This reduced the time it took the battery to recharge. About 15 minutes of charging can last more than a week. "Even after 150 charges, which would be one year or more of operation, the battery is still five times more effective than lithium ion batteries on the market today," said Kung. The technology could be widely available... Question: We can infer from the article that _ . Options: A: current rechargeable batteries usually last for 150 charges B: after one year's use, the newly developed batteries are less powerful C: batteries with more lithium ions are more powerful and charge faster D: further experiments may focus on improving the shape of graphene sheets
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B

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I'm taking a test and have to guess the right answer to the question after the article. Article: The journey two naval officers made some time ago to the very deepest point on the earth makes us realize how much of the world still remains to be explored. The two men went down seven miles to the bottom of the Pacific Ocean inside a small steel ball called a "bathyscaphe" to find out if there are any ocean currents or sings of life. It was necessary to set out early, so that the "bathyscaphe" would come to the surface in daylight, and so be easily found by the mother ship which would be waiting for it. The drivers began preparations at dawn and soon afterwards, when all was ready, the steel ball disappeared under the surface of the water. In time, the temperature dropped to freezing-point and the men trembled inside the ball. They kept in touch with the mother ship by telephone describing how they felt. Then, at a depth of 3,000 feet, the men were surprised by a sudden, loud noise, even the smallest hole in the ball would have meant instant death. Luckily, though, it was only one of the outer windows that had broken. Soon afterwards, the "bathyscaphe" touched the soft ocean floor raising a big cloud of "dust" made up of different kinds of small, dead sea animals. Here, powerful lights lit up the dark water and the men were surprised to see fish swimming just above them quite uncontrolled by the very large water-pressure. But they did not dare to leave the lights on for long, as the heat from them made the water boil. Quite unexpectedly, the telephone began working again and the weak but clear voices of the officers wre heard on the mother ship. After a stay of thirty minutes the men began their journey up, arriving three hours later, _ . Question: The journey to the bottom of the sea helped us to realize that _ . Options: A: much of the world hasn't yet been explored B: there are not any sings of life at the bottom of the sea C: strong water-pressure has great effect on fish D: powerful lights cannot be turned on at the ocean floor
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A

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I'm taking a test and have to guess the right answer to the question after the article. Article: My son and I were trying to sell the house we had repaired, but in the barn there were bats and they would not leave. The barn was their home. They told us so in their own way they hung for the season. "Don't worry about it, Dad." Patrick said. "They keep down the mosquitoes ." Unfortunately they also kept the buyers away. When we had asked a person to sell the house for us he had refused to show it because of the bats. "Bats are popular," Patrick comforted me. "They are ecological." "Isn't there a machine you can buy that produces high-frequency sounds to keep bats away?" " I don't know," said Patrick. "But I like bats, and whoever buys this house will probably like them too.' "Probably?" I hated that word. "How many bats are there, anyway?" "I counted about 90 last night," said Patrick. "They were dropping out from under the edge of the roof." "You mean there are more------outside?" "They're everywhere, Dad. But look at it this way. When the cold weather comes, they'll be off to Mexico. Maybe in the spring we can keep them out. Don't worry about it," he said for the the hundredth time. "It's not a problem." The bat expert I called was even more active than Patrick. "I think you've got a large number there," he said in wonder. "I've been trying to attract bats to our house for 25 years. A single bat ears up his weight in mosquitoes and black flies three times every night. You've a very lucky man." I offered to share my luck with him. He could take them away. "Bats have a remarkable homing instinct ," he said. "They'd fly straight back even if I transported them 100 miles. Once they have settled, you can't stop them from coming back." I was silent. Finally we managed to rent the house to a young family, who were also interested in buying it. "What about the bats?" I said to Patrick. "Oh, they love the bats," he said. "No mosquitoes. No black flies. It's one of the things that attracted them." "Do you think they will really buy the house?" "Probably? Well, if they do, I suppose I'll have to admit that I was... Question: Why did the author think he might have to "eat his words"? Options: A: He felt sorry for the bats. B: He was happy about selling the house. C: He realized they might be wrong about the bats' actions D: He might be mistaken about being unable to sell the house.
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D