China has been the birthplace of many of the world’s greatest inventions. It was, for example, the first country to produce paper money. Before the invention of paper money and coin, people used many different kinds of things for buying and selling.
In the years which followed this invention, many other countries around the world began to do the same.
About 1,000 years later, leather was used as money in China, and in 806 AD, the first banknotes were produced by the Chinese people.
| A．As time went by, trade between countries increased. |
| B．People also began collecting foreign coins as souvenirs. |
| C．They also used tiny shells as money for buying and selling. |
| D．It was still many years before paper currency appeared in Europe. |
| E．However, as the economy developed, such exchanges became impractical. |
| F．During that time, for example, buying a chicken might cost several potatoes. |
| G．The very first coins often had holes in them so that people could string them together. |
相似题推荐
【推荐1】Erin Alexander was having a hard day. A waitress working at Starbucks was too. Erin ordered an iced green tea and told the waitress to cheer up. After picking up the order, she noticed a message on the cup: “Erin, your soul is golden.” Erin Alexander recalled the incident, “Of course, I was still really sad, but that little thing made the rest of my day.”
New findings, published in the Journal of Experimental Psychology in August, prove just how powerful experiences like Erin’s can be. Researchers found that people who perform a random act of kindness tend to underestimate how much the recipient will appreciate it. And they believe that miscalculation could hold many of us back from doing nice things for others more often.
A recent experiment recruited 84 participants at an ice skating rink in Chicago, where they were given a hot chocolate and asked to keep it or give it to a stranger as an act of kindness. The 75participants who gave away their hot chocolate were asked to predict how the recipient would feel on a scale from 0(very small) to 10(very large), and the recipients were then asked to report their actual feelings on the same scales.
In that experiment, the people doing the kind thing consistently underestimated the appreciation they receive, according to Amit Kumar, a psychology professor at the University of Texas. “People tend to think that what they are giving is kind of little, maybe it’s relatively inconsequential,” Dr. Kumar said. “But recipients are less likely to think along those lines. They consider the gesture to be significantly more meaningful because they are also thinking about the fact that someone did something nice for them.” Dr. Kumar continued, “With an experiment like this, I hope it will inspire more people to actually commit random acts of kindness.”
1. What’s the function of paragraph 1?| A．To present a fact. | B．To introduce the topic. |
| C．To describe a scene. | D．To explain an opinion. |
| A．All participants give away their hot chocolate. |
| B．Recipients received kind gestures from their friends. |
| C．Recipients showed more appreciation than givers think. |
| D．Participants reported their feelings on a scale from 0 to 10. |
| A．Insignificant. | B．Substantial. |
| C．Beneficial. | D．Unbelievable. |
| A．The Power of Small Acts of Kindness. | B．The Magic of Receivers’ Appreciation |
| C．The Importance of Appreciating Kindness. | D．The Impact of a Simple Message on a Cup. |
【推荐2】Do you ever get the feeling that you’re being watched? Well, you might be right.
According to a study published in Nature on June 23, astronomers have found that 1, 715 stars have had a direct view of Earth since humans have been here.
The team looked at 331, 312 stars within 326 light-years of Earth, with each light-year equaling 9.4 trillion kilometers. Out of all those stars, only 1, 715 of them could see Earth within the last 5, 000 years, with an extra 319 stars that will be able to see us in the next 5, 000 years.
“When I look up at the sky, it looks a bit more amiable because it’s like, maybe somebody is waving,” said Lisa Kaltenegger, director of the Carl Sagan Institute at Cornell University, US, and the study’s lead writer.
If a planet circling around one of those 1, 715 stars is home to advanced life, they could easily see that there is life here because of the oxygen on Earth. If that didn’t give it away, then the radio waves we have sent out into space would also be an indicator. In fact, human-made radio waves have already traveled through 75 of the closest stars on Kaltenegger’s list.
Why haven’t we heard from anyone yet, then?
It takes a long time for messages to travel between star systems. By the time a message could be received, that advanced civilization would probably not exist anymore.
Alan Boss, a scientist at the Carnegie Institution for Science in the US who wasn’t part of the study, wrote in an email that this long time would limit the chances for different life to exchange “emails and TikTok videos”.
“So we should not expect aliens to show up anytime soon,” Boss said.
1. What does the underlined word “that” refer to?| A．A planet circling around one of those 1,715 stars. |
| B．The oxygen on Earth. |
| C．Home to advanced life. |
| D．Human-made radio waves. |
| A．Human-made radio waves cannot travel far. |
| B．Aliens don’t exist. |
| C．They cannot understand each other. |
| D．It takes a long time for messages to travel. |
| A．Indifferent | B．Critical | C．Positive | D．Negative |
| A．To present new findings published in a study. |
| B．To discuss the advanced life on other stars. |
| C．To explain the feeling that you’re being watched. |
| D．To illustrate how messages travel between star systems. |
【推荐3】Physical activity is important in preventing cardiovascular(心血管的) disease in young people so long as they don’t undertake very intense activity on days when air pollution levels are high, according to a recently released study.
Until now, little has been known about the relationships between the health benefits of physical activity taking place outdoors and the potentially harmful effects of air pollution. Previous research by the authors of the current study had investigated the question in middle-aged people at a single point in time, but this is the first time that it has been investigated in young adults aged between 20—30 years over a period of several years. In addition, the researchers wanted to see what happens when people increase or decrease their physical activity over time.
At each health check-up, the participants completed a questionnaire asking about their physical activity in the past seven days and this information was changed into units of metabolic equivalent task(MET, 代谢当量任务) minutes per week(MET-mins/week). The participants were divided into four groups: 0, 1—499, 500—999 and 1000 or more MET-mins/week. People are recommended to do 500—999 MET-mins/week and this can be achieved by; for example, running, cycling or hiking for 15—30 minutes five times a week, or brisk walking, doubles tennis or slow cycling for 30—60 minutes five times a week.
The researchers used data to calculate annual average levels of air pollution, in particular the levels of small particulate matter that are less than or equal to 10 or 2.5 microns in diameter, known a PM10 and PM25.
Overall, the results show that physical activity is associated with a lower risk of developing cardiovascular disease among young adults. However, when air pollution levels are high, exercising beyond the recommended amount may offset or even reverse the beneficial effects. The study cannot show that air pollution causes the increased cardiovascular risk, only that it is associated with it.
1. What can we know from Paragraph 2?| A．Outdoor physical activity harms our health. |
| B．Exercising isn’t advised on serious air pollution days. |
| C．A first in-depth survey has been done on young adults. |
| D．Middle-aged people have been the ideal research target. |
| A．By doing research on young adults. |
| B．By collecting PM10 and PM2.5 data. |
| C．By making experiments on middle-aged people. |
| D．By studying a questionnaire on physical activity. |
| A．Air pollution leads to cardiovascular disease. |
| B．Cardiovascular disease relates to air pollution. |
| C．More physical exercise benefits young people. |
| D．Young adults seldom develop cardiovascular disease. |
| A．Physical activity & air pollution: when to do more or less physical activity. |
| B．Physical activity & health benefit: how to prevent cardiovascular disease |
| C．Physical activity & air pollution: what to do with high air pollution levels |
| D．Physical activity & health benefit: how to maximize the health benefits of exercising |
【推荐1】How fit are your teeth? Are you lazy about brushing them? Never fear: An inventor is on the case. An electric toothbrush senses how long and how well yon brush, and it lets you track your performance on your phone.
The Kolibree toothbrush was exhibited at the International Consumer Electronics Show in Las Vegas this week. It senses how it is moved and can send the information to an Android phone or iPhone via a Bluetooth wireless connection.
The toothbrush will be able to teach you to brush right (don't forget the insides of the teeth) and make sure you're brushing long enough. “It's kind of like having a dentist actually watch you brushing on a day-to-day basis,” says Thomas Serval, the French inventor.
The toothbrush will also be able to talk to other applications on your phone, so developers could, for instance, create a game controlled by your toothbrush. You could score points for beating monsters among your teeth. “We try to make it smart but also fun,” Serval says.
Serval says he was inspired by his experience as a father. He would come home from work and ask his kids if they had brushed their teeth. They said “Yes”. But Serval would find their toothbrush heads dry. He decided he needed a brush that really told him how well his children brushed.
The company says the Kolibree will be on sale this summer, from $99 to $199, developing on features. The USA is the first target market.
Serval says that one day, it'll be possible to replace the brush on the handle with a brushing unit that also has a camera. The camera can even examine holes in your teeth while you brush.
1. Which is one of the features of the Kolibree toothbrush?| A．It can help users find their phones. |
| B．It can track users' school performance. |
| C．It can detect users' fear of seeing a dentist. |
| D．It can sense how users brush their teeth. |
| A．You will find it enjoyable to see a dentist. |
| B．You can brush with the Kolibree as if guided by a dentist. |
| C．You should see your dentist on a day-to-day basis. |
| D．You'd like a dentist to watch you brush your teeth every day. |
| A．They preferred to use a toothbrush with a dry head. |
| B．They often failed to clean their toothbrushes. |
| C．They were unwilling to brush their teeth. |
| D．They liked brushing their teeth after Serval came home. |
| A．The brush handle will be removed. |
| B．A mobile phone will be built into it. |
| C．It will be able to check users' teeth. |
| D．It will be used to fill holes in teeth. |
【推荐2】Commercial airlines alone contribute around 3% of total global carbon emissions. But the industry is actively looking for green solutions in the form of sustainable jet fuel, and in one case, that fuel may have had a previous life as your household food waste. In a study released this week in the Proceedings of the National Academy of Sciences, researchers detail a method of transforming food waste into sustainable jet fuel that can be used in existing engines.
Biomass (生物质), such as manure (粪便) and food waste, can be transformed into bio-fuels, which are renewable liquid fuels made from organic matter. Derek Vardon, a senior research engineer at the National Renewable Energy Laboratory (NREL), says that their fuel worked as a mixture of 90% conventional petrol jet fuel and 10% alternative jet fuel required by the industry currently. They also show they could push it to a 70/30 mixture, which will be possible in real world with more time and testing.
Major airline companies are eager to get involved in sustainable aviation fuel because some sustainable solutions, such as battery-operated commercial planes, just aren’t possible yet with current battery technology. A battery-powered plane would be too heavy to fly long distances, so fuel that works in the same way as the fuel we have is a simpler way to trade out emission-heavy fossil fuels.
Vardon says that because the wet waste used in the process would normally go to a landfill (垃圾填埋场) and break down to release greenhouse gases, the process of making and using sustainable aviation fuel could actually have a negative carbon footprint when scaled up.
Commercial airlines are on board to find an affordable and sustainable solution to the carbon-intensive process of air travel. Airlines are looking to hit aggressive sustainability goals by 2050, including decreasing net carbon dioxide emissions by 50%.
1. Which of the following is used for sustainable airline power?| A．Fossil fuel. | B．Liquid fuel. | C．Battery power. | D．Biomass. |
| A．Fuel-powered planes are likely to travel lighter and farther. |
| B．Biofuel is environmentally friendly and sustainable. |
| C．It’s convenient to create the proper fuel mixture. |
| D．Biofuel proves less costly and easier to produce. |
| A．taking off. | B．holding a meeting. |
| C．participating in. | D．appearing on stage. |
| A．Alternative Energy to Fossil Fuel. |
| B．How to Get Fossil Fuel Sustainable. |
| C．Changing Food Waste into Airplane Fuel. |
| D．How to Decrease Carbon Dioxide Emissions. |
【推荐3】Brown cows may not actually make chocolate milk, but pink silkworms（蚕）do produce pink silk, a team of scientists has discovered. To see if they could produce pre-dyed silk-silk that comes colored, straight from the source-the team fed ordinary silkworms mulberry（桑树）leaves that had been sprayed（喷洒）with fabric（织物）dyes（染色剂）. Out of seven tested dyes, only one worked, producing a thread that reminded me of pink-dyed hair.
And yes, the worms themselves take on some color before they produce silk. Their colorful diets did not affect their growth, the team, which included engineers and biologists from the CSIR-National Chemical Laboratory in India, reports in the journal ACS Sustainable Chemistry & Engineering. (The researchers didn't look too deeply into how the dyes affected the silkworms' health. After all, silkworms die when people harvest their silk.)
The team made dyeing silk this way because coloring fabric normally uses large amounts of fresh water. The water gets polluted with dangerous chemicals in the process, requiring costly treatment before factories can send it back into waterways. Dyeing silk directly by feeding silkworms would avoid those water-washing steps. Scientists are just starting to study this idea. However, it remains to be seen if it's commercially successful. In this experiment, the Indian team tested seven dyes, which are cheap and popular in the industry.
The scientists found different dyes moved through silkworms' bodies differently. Some never made it into the worms' silk at all. Others colored the worms and their silk, but the color disappears before the silk is turned into fabric. Only one dye, named "direct acid fast red", showed up in the final, washed silk threads. By the time it made it there, it was a pleasant, light pink.
1. The text is most probably a(n) ________.| A．science report | B．tourist guide |
| C．animal experiment | D．fashion advertisement |
| A．they are born pink | B．they are dyed pink |
| C．they grow in pink water | D．they are fed dyed food |
| A．In America. | B．In India. | C．In Israel. | D．In China. |
| A．One. | B．Three. | C．Five. | D．Seven. |
