The forest in Senegal, a country in western Africa, is full of the chimps' usual noises. Suddenly dogs bark. Larger male chimps drop from the trees to face the threat while the others climb to safety. Then the dogs' young human masters appear.

One mother chimp with a tiny baby tries to run. The dogs attack and separate them. The two teenage boys quickly catch the baby chimp. But they don't act out of sympathy — they save the baby so they can sell it.

    After the teenagers return to their hometown, they visit a man who is said to be very interested in chimps. When they ask the man, Johnny Kante, if he wants to buy the baby, he replies, “That's not what we do.” Kante is a member of a scientific team. Although Kante is angry with the teens for capturing the chimp, he hides his anger and persuades them to take him to the baby chimp.

    Unsure of what to do next upon seeing the chimp, Kante calls Jill Pruetz, the head of the chimp research team. “I'm really worried,” says Pruetz, doubtful that the mother is still alive. But knowing that wild chimps sometimes adopt orphans（孤儿）， Kante and pruetz decide they must try to return the baby chimp to its wild community.

    Kante pays another visit to the teenagers. After he explains how much trouble they are in, because chimps are an endangered species, he requests they should give him the frightened baby without payment. They agree. Kante takes the baby chimp to his home and feeds her milk from a bottle whenever she cries.

    The next morning, Pruetz and Kante leave the baby with another team member and begin their search for the wild chimps. Pruetz quickly finds the group in the woods. She recognizes the female that is without her child.

    Pruetz is so excited that she runs the entire mile back to bring the baby chimp to the tree where the chimps are hanging out. The researchers place the baby on the ground near the tree and back away. Almost immediately, a male chimp drops to the ground and stares at the baby curiously. He carries her back to where the mother is waiting.

    Pruetz still can't believe how fortunate they were to have reunited the mother and child. “Surprising is the only word I can think of,” she says.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    Homesick is a compound word made up of HOME and SICK. You know what each word means on its own, of course. But think about what the words mean when they are used together. Homesick means SICK FOR HOME.

    Now think for a minute about SEASICK. If you change the word home in the definition(释义)to the word sea, would the definition fit SEASICK? Seasick means SICK BY THE MOVEMENT ON THE SEA. When you are homesick, the only place you want to be is at home. When you are seasick, the last place you want to be is at sea.

    Have you ever heard of a person being heartsick? Heartsick doesn't mean that something is wrong with a person's heart, people are heartsick when they are hurt deep inside and when they feel as if their hearts are broken.

    But, on the other hand, we have such compound words as handshake, handstand, and handbag. Perhaps you may write definitions for them.

    The Chicago Fine Chocolate Show took place in November. Pastry chefs (面包师) from around the country handed out samples of their very best work. Chef Scott Green, a chocolate sculptor, impressed the attendees at the show. Not only did he bring his work for all to see，but he also made chocolate sculptures right then and there.

    Green talked to TFK about his job as a chocolate sculptor. He explained that he thinks of himself as an artist who just happens to work with chocolate rather than wood or stone. “I have been around chocolate so long that it isn't chocolate anymore,” he said. To learn more about the job of a chocolate sculptor, read on.

    TFK: What was the hardest thing that you have ever carved, and what was it made of?

    GREEN: In 2017, I did the U.S. Pastry Championship, and I had to carve it castle out of white chocolate for the competition. I didn't have a lot of experience, and white chocolate is hard to carve. That was the hardest thing I have ever carved.

    TFK: How long does it take to make an average sculpture?

    GREEN: For me, it takes a couple of days. Most of that time is getting all the pieces ready. The easiest part is gluing it all together. Chocolate is used for glue. It holds together very well.

    TFK: How much chocolate do you use per sculpture?

    GREEN: It depends on the sculpture. For a show piece, I maybe use 20 to 60 pounds of chocolate. You have to be really strong to lift it. I always ask for help.

    TFK: Is it easier to work with sugar or chocolate?

    GREEN: They are very different. Generally speaking, it is easier to work with chocolate. Chocolate likes being poured into molds (模具), and it sets at room temperature. Sugar is much more fragile. It is very hot when you work with it and not as easy.

How Much Can We Afford to Forget?

    In 2018, Science magazine asked some young scientists what schools should teach students. Most said students should spend less time memorizing facts and have more space for creative activities. As the Internet grows more powerful, students can access(获得)knowledge easily. Why should they be required to carry so much of it around in their heads?

    Civilizations(文明)develop through forgetting life skills that were once necessary. In the Agricultural(农业的)Age, a farmer could afford to forget hunting skills. When societies industrialized, the knowledge of farming could be safe to forget. Nowadays, smart machines give us access to most human knowledge. It seems that we no longer need to remember most things. Does it matter?

    Researchers have recognized several problems that may happen. For one, human beings have biases (偏见), and smart machines are likely to increase our biases. Many people believe smart machines are necessarily correct and objective, but machines are trained through a repeated testing and scoring process. In the process, human beings still decide on the correct answers.

    Another problem relates to the case of accessing information. When there were no computers, efforts were required to get knowledge from other people, or go to the library. We know what knowledge lies in other brains or books, and what lies in our heads. But today, the Internet gives us the information we need quickly. This can lead to the mistaken belief — the knowledge we found was part of what we knew all along.

    In a new civilization rich in machine intelligence, we have easy access to smart memory networks where information is stored. But dependency on a network suggests possibilities of being harmed easily. The collapse of any of the networks of relations our well-being(健康)depends upon, such as food and energy, would produce terrible results. Without food we get hungry; without energy we feel cold. And it is through widespread loss of memory that civilizations are at risk of falling into a dark age.

    We forget old ways to free up time and space for new skills. As long as the older forms of knowledge are stored somewhere in our networks, and can be found when we need them, perhaps they're not really forgotten. Still, as time goes on, we gradually but unquestionably become strangers to future people.

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. "

Plants may tell us when they're in trouble.Thirsty tomato and tobacco plants make clicking sounds,researchers have found.The sounds are ultrasonic (超声波的),meaning they are too high-pitched for human ears to hear.But when the sounds are transformed to lower pitches,they sound like popping bubbles (爆破的泡泡).Plants also make clicks when their stems (茎) are cut.

"It's not like the plants are screaming," says Lilach Hadany,an evolutionary biologist working at Tel Aviv University in Israel."Plants may not mean to make these noises.We've shown only that plants create informative sounds."

Hadany and her colleagues first heard the clicks when they set microphones next to plants on tables in a lab.The microphones caught some noises.But the researchers needed to make sure that the clicking was coming from the plants.So,the scientists placed plants inside soundproof boxes in the basement,far from the noise of the lab.There,microphones picked up ultrasonic pops from thirsty tomato plants.Though it was outside humans' hearing range,the clicking made by plants was about as loud as a normal conversation.

Cut tomato plants and dry or cut tobacco plants clicked,too.But plants that had enough water or hadn't been cut stayed mostly quiet.Wheat,corn and grapevines also made sounds when stressed out.

The researchers don't yet know why plants click.Bubbles forming and then popping inside plant tissues that transport water might make the noises.But however they happen,pops from crops could help farmers,the researchers suggest.Microphones,for example,could monitor fields or greenhouses to detect when plants need to be irrigated (灌溉).

Hadany wonders whether other plants and insects already tune into plant pops.Other studies have suggested that plants respond to sounds.And animals from pests (害虫),moths to mice can hear in the range of the ultrasonic clicks.Sounds made by plants could be heard from around five meters away.Hadany's team is now studying what the living things near the plants will do after hearing the sounds.