选择知识点

B

My problems started after I went to a boarding（寄宿）school. I was only 14, and at first I missed my family a lot. I often called them and cried on the phone. But after two weeks, I found that I enjoyed being with my classmates at school. I had many friends who were boys. I thought of them as my best friends – but only friends. I never guessed my friendships with boys would become a problem.

Then, three months later, my friends told me that some teachers and girls said I was staying with boys all day long in order to get attention from them. Seven months after that, the head teacher Mr. Wang asked the class to choose some students to join the Student Union(学生会). I thought I could win , for I was doing well in school. I had already won prizes for the best math and English exams. A week later, the list came out and it didn’t include me. I was sad.

Mr. Wang came to me and said, “Don’t be sad. I know you’re excellent! Maybe you are a little distant from the girls in our class. They don’t know much about you, so some of them didn’t choose you. It doesn’t matter. Do your best to get along well with everyone and I think you’ll make it next time.”

    A recent survey found that only 9% of teens in the United States smoke cigarettes．That's down from 23% in 2000．While this is good news for America's overall health，tobacco use is still a problem．

    According to the American Lung Association，every day almost 3，900 children under 18 years of age try their first cigarette，and more than 950 of them will become daily smokers．If the trend continues at its current rate，5.8 million children alive today will die of smoking．

    The Truth campaignis working to end teenage smoking all together．Their latest“Finish It”series uses social media to spread awareness about the dangers of smoking．“If we all join forces—smokers and non-smokers—we can end smoking once and for all，”the campaign website states．The campaign encourages teens to not judge，but instead to learn the facts．

    However，another issue surfaces．A 2013 report from the Center for Disease Control found that use of electronic cigarettes，battery-powered devices，is on the rise．“The increased use of e-cigarettes by teens is deeply troubling，”said CDC Director TomFrieden，M．D．，M．P．H．“Nicotine is a highly addictive drug．Many teens who start with e-cigarettes may struggle with a life long addiction．”

    Scientists are still researching exactly how harmful e-cigarettes are．“This is cause for great concern as we don't yet understand the long-term effects of these novel tobacco products，”said Mitch Zeller，director of FDA's Center for Tobacco Products．

    This year，the pharmacy chain CVS made a move to fight the tobacco trend．It became the first nationwide pharmacy to ban sales of cigarettes and tobacco products at its U．S．stores．The decision came after years of pressure from health experts．

    With the obvious danger of tobacco，anti-smoking campaigns have become more popular．Some college campuses and other outdoor areas across the country have banned smoking altogether．

    On October 27，21，615 children and teens joined the Truth campaign and pledged not to smoke．The group hopes they can give teens and young people the knowledge to“be the generation that ends smoking．”

A

    Are you a bit bored with your nine-to-five routine? Have a look at our exciting range of holidays and decide what type of adventure you’d like.

    Activity holidays Our activity holidays are for everyone who loves danger. We have a huge of water, snow and desert holidays. We’ll take you scuba diving(戴水肺潜水）in the Red Sea of kayaking (皮划艇）and white water rafting in Canada.     

    If you prefer snow, you can try skiing or snowboarding in the Alps or even igloo-building(搭建冰屋). For those who like warm weather, we also have sand boarding (the desert version of skateboarding) or camel safaris.

    Polar expeditions Take a cruise to the Antarctic or the Arctic; explore a land of white nature beauty or wonderful wildlife. Our experts will explain everything about the two poles as you watch penguins or whales in the Antarctic and polar bears in the Arctic. There's no greater adventure than traveling to the two ends of the earth.

    Culture journeys Our culture journeys will help you discover the secrets of distant places such as India, Thailand or Egypt. Explore their history by visiting temples, palaces and ancient ruins. You can also get to know how people live in the modern world by exploring markets, eating exotic foods and meeting local people.

Hiking tours We have hiking holidays to famous places, such as Machu Picchu or the Everest Base Camp Trek, as well as some nearer to home, for example in the highlands of Scotland. You don't need to be too sporty, just fairly fit.  

    You’ll have a great time enjoying nature with a group of new friends. Some of the holidays need camping, but we'll transport the tents for you!

    Wildlife holidays We organize small group tours to get closer to nature in Africa, Asia or South Africa. Go on safari in Africa and watch lions and giraffes.   

    Meet the famous turtles of Galapagos Islands. Look for tigers in India, or take an elephant safari in Sri Lanka. We use local guides and stay in a range of accommodation, from tents to tree houses.

   B

You may think, salt is just a simple cooking element we shake on our food for a little extra taste. But salt is much more than that. Without salt, Our muscles would not move. Our nervous systems would not operate. Our hearts would not beat.

But do not think rubbing salt in a wound will help. Doing that would be painful and not heal the wound.To rub salt in a wound is an idiom that means to purposefully make a bad situation worse.

Early humans got the salt they needed to stay alive from the animals they killed. But advances in agriculture led to a diet low in salt. So, humans needed to find other sources. Those who lived near the ocean or other natural sources for salt were lucky. Those who did not had to trade for salt. In fact, people used salt as a method of payment in many parts of the ancient world. The word "salary" comes from the word "salt".

Salt also played an important part in population movement and world exploration. Explorers understood that if they could keep food fresh, they could travel longer distances. So they used salt to preserve food and explored the world.

Salt was so important that, according to food historians, it was traded pound-for-pound

for gold. Today, people still use the expressions “to be worth one's salt” or “worth one's weight in salt”. The expressions describe a person who is helpful, a person of value.

A person might also be called “salt of the earth”. That description means he or she is dependable and trustworthy. However, when you say "I think we should take what he said with a grain of salt" you mean you accept it but maintain a degree of doubt about its truth.

 D

    Controlling traffic is a complex and high cost problem in many developed countries. It becomes more difficult and costly with the ever-increasing number of cars on the roads. But scientists and students at the CATT, at the University of Maryland, are working to solve this problem. They are using simulation(模拟) technologies to help government and private business control and react to changing traffic conditions.

   The online economics magazine Forbes.com says traffic congestion(拥挤) cost Americans $ 124 billion in 2014 and that number could rise to $ 186 billion by 2030.

   But scientists at the CATT lab are trying to reduce those costs. They are developing a system that helps traffic managers, planners, emergency workers and businesses plan and react better. Michael Pack is CATT director. He says the system is important to help emergency workers, or first responders, reach an accident area faster.

   The CATT Lab collects information from many sources, including roadside devices, GPS (global positioning system) equipment and wireless phones.

   About 60 students and 30 software developers observe traffic flow and manage the computer servers at all times. They also work to develop software and applications that can help traffic run smoother and safer, Some of them turn the information gathered into so-called "visualizations". These visual representations help emergency workers better understand what is happening.

   The center shares its findings with firefighters, police, transportation departments and the military. They also share information with universities and the technology company. Google uses the data for its traffic-related websites. Michael Pack says, the information is then shared with anyone who wants to help traffic run more smoothly.

    Mr. Pack says the goal is to help develop an intelligent system of road signals that will communicate with each other and with vehicles on the road.