Coffee is one of the most popular drinks around the world.{#blank#}1{#/blank#}Expertsclaim that there are more flavors of coffee than there are of wine. Coffee contains caffeine, an element (成分) that raises our awareness, keeps us from falling asleep or simply gives us a kick in the morning or after lunch.

{#blank#}2{#/blank#} For a longtime doctors have told people not to drink too much coffee, because it may leadto heart problems, high blood pressure, insomnia (失眠) andheadaches.

        Scientists have now found out that it isthe quality of coffee and the way it is brewed (冲泡) that holds the key to our health.  {#blank#}3{#/blank#} Among other things, this is linked to the consumption of a strong brew of coffee. Experts also point out that different roasts and types of coffee beans have different effects on our health.

        A new study by a Harvard research groupsays that there is no link between coffee and health problems.{#blank#}4{#/blank#}Doctors, however, warn against drinking too much coffee, as it can lead to stomach problems.

        Coffee has many advantages, as the newstudy suggests. While alcohol makes people sleepy and slow-moving, coffee givesthem energy.{#blank#}5{#/blank#}

        Although a lot still needs to be uncovered about coffee, it seems to reduce the risk of cancer and diabetes.Reports show that people who drink coffee may develop Parkinson's disease laterin life, or maybe not at all.

A. There are many different types ofcoffee.

B. Scientists ask people not to drinkcoffee at night.

C. Elderly people in Greece live longerthan normal.

D. But experts are still undecided onhow healthy coffee is.

E. Sugar can change the different levelsof caffeine in a cup of coffee.

F. Drinking several cups of coffee a dayis not connected with heart diseases.

G. Getting together for a cup of coffeealso has a positive effect on relationships.

    Hummingbirds(蜂鸟) are one of nature's most energetic fliers and the only birds to hover(盘旋) in the air by relying on their strength alone.

    Now scientists have found that it is the ratio(比值) of the bird's wing length to its width that makes them so efficient. The discovery is helping experts compete with 42 million years of natural selection to build helicopters that are increasingly efficient.

    David Lentink, an assistant professor at Stanford University in California, tested wings from 12 different species of hummingbirds, which he sourced from museums. He placed them on a machine used to test the aerodynamics(气力学) of the helicopter blades(桨叶). Professor Lentink's team used the same machine to test the blades from an advanced micro-helicopter used by the UK's army. They found that the micro-helicopter's blades are as efficient at hovering as the average hummingbirds.

    But while the micro-helicopter's blades kept pace with the average hummingbird wings, they could not keep up with the most efficient hummingbird's wing. The wings of Anna's hummingbird were found to be about 27 percent more efficient than the man-made micro- helicopter's blades.

    While Professor Lentink wasn't surprised at nature's superiority, he said that helicopter blades have come a long way. “The technology is at the level of an average hummingbird,” he said. “A helicopter is really the most efficient hovering device that we can build. The best hummingbirds are still better, but I think it's amazing that we're getting closer. It's not easy to match their performance, but if we build better wings with better shapes, we might match hummingbirds.”

    Professor Lentink said that we don't know how hummingbirds maintain their flight in a strong wind, how they navigate(确定方向) through branches, or how they change direction so quickly. He thinks that great steps could be made by studying wing aspect ratios-the ratio of wing length to wing width. Understanding these abilities and characteristics could be a benefit for robotics and will be the focus of future experiments.

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。

    Scientists have been studying how people use money for long. Now they're finding some theories may apply to one group of monkeys.

    Researchers recently taught six monkeys hos to use money. They gave the monkeys small metal disks (圆片) that could be used like cash and showed them some yummy apple pieces. The monkeys soon figured out that if they gave one of the disks to a scientist, they'd receive a piece of apple in return.

    If you think that is all the monkeys can figure out, you are wrong. Two researchers, Jake and Allison, acted as apple sellers in the experiments. The monkeys were tested one at a time and had 12 disks to spend in each experiment. Jake always showed the monkeys on apple piece, while Allison always showed two pieces. But that's not necessarily what they gave the monkeys. The number of apple pieces given for a disk was determined at random.

    Experiment One: Allison showed two pieces of apples but gave both piece only half the time. The other half, she took one piece away and gave the monkey just the remaining piece. Jake, on the other hand, always gave exactly what he showed: one piece for each disk. The monkeys chose to trade more with Allison.

    Experiment Two: Allison continued to sometimes gave two pieces and sometimes one piece. But now, half the time, Jake gave the one apple piece he was showing, and half the time he added a bonus. Guess what? The monkeys chose to trade more with Jake.

    In the first experiment, the monkeys correctly figured out that if they traded with Allison, they'd end up with more treats. In the second one, when a monkey received two pieces from Jake, it seemed like a gain. When Allison gave the monkey only one piece instead of the two she showed, it seemed like a loss. The monkeys preferred trading with Jake because they'd rather take a chance of seeming to win than seeming to lose.

    We also sometimes make silly business decisions just to avoid the feeling that we're getting less, even when we're not. Would you have made the same choices?

    Eyesight plays a very important role in our daily life. Every waking moment, the eyes are working to see the world around us. Over forty percent of Americans worry about losing eyesight, but it's easy to include steps into our daily life to ensure healthy eyes. Here are five suggestions for a lifetime of healthy eyesight：

    Schedule yearly exams. {#blank#}1{#/blank#}Experts advise parents to bring babies 6 to 12 months of age to the doctor for a careful check. The good news is that millions of children now can have yearly eye exams and following treatment, including eyeglasses.

    Protect against UV rays (紫外线). Long term stay in the sun creates risk to your eyes. No matter what the season is, it's extremely important to wear sunglasses. {#blank#}2{#/blank#}

    Give your eyes a break. Two thirds of Americans spend up to seven hours a day using computers or other digital products. {#blank#}3{#/blank#}Experts recommend that people practice the 20/20/20 rule: every 20 minutes, take a 20second break and look at something 20 feet away.

    {#blank#}4{#/blank#}As part of a healthy diet, eat more fruits and vegetables each day. Vitamins C and E help protect eyesight and promote eye health.

    Practice safe wear and care of contact lenses (隐形眼镜). Many Americans use contact lenses to improve their eyesight. While some follow the medical guidance for wearing contact lenses, many are breaking the rules and putting their eyesight at risk. {#blank#}5{#/blank#} Otherwise, you may have problems such as red eyes, pain in the eyes, or a more serious condition.

A．Eat your greens.

B．Eye care should begin early in life.

C．They can properly protect your eyes.

D．Stay in good shape by taking more vitamins.

E．Parents usually don't care about their own eyesight.

F．Always follow the doctor's advice for appropriate wear.

G．This frequent eye activity increases the risk for eye tiredness.

    People from all over the world visit Disneyland to have fun, not to get sick. But last week, an outbreak of measles(麻疹)spread from the Southern California theme park. As of Monday, January 19, at least 52 people have got the easily spread illness.

    The majority of the reported cases of measles are from people who visited the park before. According to the California Department of Public Health, these people were exposed to the illness at Disneyland from December 17-20.

    Officials believe the cause is likely someone who caught measles abroad and visited Disneyland, but this has yet to be proved. However, in 2014, California had its highest measles infection rate in nearly twenty years. There were 66 cases of measles reported in the state―23 of them in Orange County, where Disneyland is located.

    Measles spreads very easily. It can be caught from coughing and sneezing. Crowded areas like theme parks are especially suitable for its spread.

    The illness starts with a fever and develops into symptoms including a cough, runny nose, red eyes and so on. About three out of ten people infected with measles will develop another health problem, including an ear infection or pneumonia(肺炎).

    The best way to guard against measles is to get vaccinated(打疫苗). An unvaccinated person is 35 times more likely to catch measles than someone who received a vaccination.

High on the Qinghai-Xizang Plateau {#blank#}1{#/blank#}(lie) China's "water tower" Sanjiangyuan. It is home to the headwaters of China's three rivers: the Yellow River, Yangtze River, and Lancang (Mekong) River. It is the three rivers {#blank#}2{#/blank#} provide water for about half the population of China. However, human activities are putting this ecosystem {#blank#}3{#/blank#}risk. Hopefully, though, we can change this damage. In 2016, the Chinese government built Sanjiangyuan National Park in Qinghai province. The park, {#blank#}4{#/blank#}(schedule) to open in 2020, has increased the area's green coverage and attracted more wildlife. The local government has also made great effort to improve biological diversity. The success of Sanjiangyuan will mark the start of a {#blank#}5{#/blank#}(green) future. With Sanjiangyuan {#blank#}6{#/blank#}(take) the lead, nine other regions in China {#blank#}7{#/blank#}(choose) by a field conservation station to carry out projects over the past three years, {#blank#}8{#/blank#} will form a national park system together. The idea of a national park system is still new in China, but{#blank#}9{#/blank#}(it) realization is urgent. After all, building an ecological civilization bears great{#blank#}10{#/blank#}(important) in the development and progress of human civilization.