I came to study in the United States a year ago. Yet I did not know the real American society until I was injured in a car accident because after the accident I had to see a doctor and go to court.   

    After the accident, my roommate called a doctor for me. I was very grateful and determined to repay him one day. But the next day, he asked me to pay him $200 for what he had done. I was astonished. He had good reason to charge me, he said. And if I wanted to collect money from the person who was responsible for my injury, I'd have to have a good lawyer. And only a good doctor can help me get a good lawyer. Now that he had helped me find a good doctor, it was only fair that I should pay him.  

    But every day I went to see the doctor, I had to wait about 50 minutes. He would see two or three patients at the same time, and often stop treating one so as to see another. Yet he charged me $115 each time. The final examination report consisted of ten lines, and it cost me $215.    

    My lawyer was all smiles the first time we met. But after that he avoided seeing me at all. He knew very well the other party was responsible for the accident, yet he hardly did anything. He simply waited to collect his money. He was so irresponsible that I decided to dismiss him. And he made me pay him $770.    

    Now I had to act as my own lawyer. Due to my inexperience, I told the insurance company the date I was leaving America. Knowing that, they played for time and I left without getting a cent.

    Over the last week, a "poisonous kale（甘蓝菜）" theory has been going widespread after an article warned that the vegetable was associated with a variety of medical conditions. It's time to separate fear from fact on the health benefits of kale.

    As a member of the cabbage family, kale is low in calories and rich in nutrients and minerals, especially vitamin A,C and K. Consumed for thousands of years, it's been a health plus for millions of eaters throughout the world.

    However, numerous web articles have reported on some evidence offered by a medicine researcher. The researcher found that thallium（铊）was detected in a few people who were heavy consumers of kale. Thallium is a heavy metal often found in trace amounts（微量）in soil and minerals. His conclusion was that these medical conditions were connected to the impact that trace amounts of thallium detected in some kale samples had on the body.

    I don't think the conclusion is based on a strict scientific basis. It's essential to point out that the original report was in a web magazine, not a scientific journal which is subject to peer review by other scientists. A scientific review includes a careful evaluation of how the findings and conclusions were made. Certain factors are critical before an evidence-based conclusion can be made, such as: how many people were in a study; how well controlled were other factors; how much kale was consumed and for how long; how much thallium was in the kale.

    It is a fact that kale and other vegetables can absorb thallium from the soil. But the ability for a plant to absorb traces of a chemical does not automatically make it harmful to your health. And even finding measurable amounts of thallium in someone's body doesn't imply that the thallium is causing an ill health effect, according to the CDC.

    But we can still learn a lesson from this. Plants grow in soil. Growers must continue to be careful in monitoring the quality of their soil. And what about consumers? Eat your kale—and include lots of other colorful fruits and vegetables. As with all things in nature, variety is key for good health.

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。

    Gardening can be a very relaxing hobby for many people and this wonderful experience is not just for adults. Children are interested in gardening as well, if given the chance to explore nature and science in this way. Gardening can bring joy to both children and their parents alike, especially when the experience is shared together.

    The time that is spent gardening together builds precious memories within their hearts and minds for years to come. When you are gardening with your children, try to give them their own special area. Keep their area in the center of the best soil and light, as you want to make sure of a successful gardening experience.

    Plastic tools easily break and are difficult to use in the dirt, so when you are gardening with your children, give them real tools to use if possible. Even offering to let them use your tools is a way to admit the worth of the work they are doing. It is also important to talk with your children about the whole process of gardening, from planting to the harvest. They need to understand how things work and the importance of what they are doing.

    Show off the children's gardening work by taking friends and visitors for a walking tour through the garden and point out the children's particular spot. When you give attention to the children's work, this is a great motivation（动机） for children to continue wanting to be involved. Do not force children to take part when they are in a bad mood or if they are becoming bored. Instead, allow them to do something different, like building a scarecrow(稻草人)! This makes the gardening experience even more interesting. As you work together side by side with your children, you will encourage a love of the land in them, as well as creating lasting memories of time spent with you.

                                                                      Amazon Best Sellers: Best Books

    A Higher Loyalty: Truth, Lies, and Leadership-April 17, 2018by James Comey

    In his book, former FBI director James Comey shares his never-before-told experiences from some of the highest-risk situations of his career in the past two decades of American government, exploring what good, ethical（道德的）leadership looks like, and how it drives sound decisions. His journey provides an entry into the corridors of power, and a remarkable lesson in what makes an effective leader.

    Hardcover $17.99

    12 Rules for Life: An Antidote to Chaos- January 23, 2018 by Jordan B. Peterson

    What does everyone in the modern world need to know? Famous psychologist Jordan B. Peterson's answer to this most difficult of questions uniquely combines the hard-won truths of ancient tradition with the great findings of most-advanced scientific research.

    Hardcover $15.57

    How to Read a Book: The Classic Guide to Intelligent Reading Revised Edition by Mortimer J. Adler, Charles Van Doren

    With half a million copies in print, How to Read a Book is the best and most successful guide to reading comprehension for the general reader, completely rewritten and updated with new material. Originally published in 1940, this book is a rare phenomenon, a living classic that introduces and clarifies the various levels of reading and how to achieve them-from elementary reading, through systematic skimming and inspectional reading, to speed reading.

     Paperback $10.31

    Everybody, Always: Becoming Love in a World Full of Setbacks and Difficult People- April 17, 2018 by Bob Goff

    Paperback $10.19

    What happens when we stop avoiding difficult people and simply love everyone? In his wildly entertaining and inspiring follow-up to the New York Times bestselling phenomenon Love Does, Bob Goff takes readers on a life-altering journey into the secret of living without fear, care, restriction, or worry.

    If humans pump enough carbon dioxide (CO₂) into the atmosphere, the stratocumulus clouds(层积云) could disappear, and the earth's temperature could climb sharply to heights not predicted in current climate models. It would burn the planet. That's the conclusion of a paper published in the journal Nature Geoscience and described in detail by Natalie Wolchover for Quanta Magazine.

    As Wolchover explained, clouds have long been one of the great uncertainties of climate models. Computer models that easily capture the complexity and detail of most climate systems just aren't powerful enough to predict worldwide changes in cloud behavior. But clouds are important. They reflect sunlight away from the earth's surface. And stratocumulus clouds are those white blankets you might have seen as you looked out the window of arm airplane, rolling out below you and hiding the ground Researchers suspect that certain sudden, past jumps in temperature may have been caused by changes to clouds like these.

    For the new research, scientists modeled just a small patch of sky using a supercomputer. They found that if carbon dioxide levels reach about 1, 200 parts per million(ppm) in the atmosphere, stratocumulus clouds break up. That's a very high carbon dioxide concentration.  Right now, levels have climbed past 410 ppm--a dangerous change from 280 ppm before the Industrial Revolution.

    But humans put more and more CO₂ into the atmosphere every year. If current trends continue, the earth could reach 1, 200 ppm within 100 to 150 years. This could happen if our society doesn't follow through on any of its commitments to reduce emissions(排放), Wolchover reported. And even if it does, the result would be another 8 degrees Celsius of heat added to the global average, on top of the dangerous changes already underway due to greenhouse gases.

    That's an enormous change, and it goes beyond predictions of worldwide ice melt and catastrophic sea level rise. And, once the stratocumulus clouds are gone, Wolchover reported, they likely wouldn't reappear until atmospheric carbon dioxide levels dropped below where they are currently.

    There's still some uncertainty in the data. The 1, 200 ppm figure could change as scientists look into the issue further.

Benefits and Problems of Genetic Engineering

    Plant breeding is the science of changing the characteristics of plants in order to produce desired ones. Genes in a plant are what determine what type of characteristics it will have. Plant breeders try to create a specific outcome of plants and potentially new plant varieties by changing the genes of the plants through breeding, which is making new plants from parents of different varieties or species.

    Actually, plant breeding has been practiced for thousands of years, since near the beginning of human civilization. It is practiced worldwide by individuals such as gardeners and farmers and by professional plant breeders employed by organizations such as government institutions, universities, crop-specific industry associations or research centers. They have crossbred plants to create the new types of plants that are, for example, bigger, stronger, or more attractive.

    Crossbreeding can take such a long time, however, and it is inaccurate. Now, we can change exact sections of Deoxyribonucleic acid (DNA), so the process is more accurate and faster. But people all over the world are arguing about its benefits and disadvantages. Some people use the technology to produce desired characteristics of plants and animals. Other people are concerned that the genetically engineered plants may harm the environment and worried that they may be dangerous for people to eat.

    There are many reasons for changing plants in this way. International development agencies believe that breeding new crops is important for ensuring food security by developing new varieties that are higher yielding(高产的), disease resistant, drought tolerant or regionally adapted to different environments and growing conditions. For example, some genetically engineered plants can live through frost or draught. As a result, famers can make more profit because fewer plants will die.

    Some genetically engineered plants are more nutritious. They have less fat, taste better or stay fresher than non-genetically engineered plants. This will allow people to buy better-quality fruit and vegetables.

    Some genetically engineered plants can resist natural pests such as viruses or insects. This reduces the amount of chemical needed to kill pests, which is helpful to the environment.

    However, genetically engineered plants can cause unexpected problems. Genetically engineered plants that resist pests may pass on that characteristic to a wild relative. This may cause the wild plant to spread fast, because pests are not naturally killing it.

    Genetically engineered plants can also harm animals. A type of corn has been developed which kills a species of insect that destroys it. The pollen (花粉) from this corn, however, can also kill monarch butterflies—the most beautiful of all butterflies, which do not harm the corn.

    To ensure the most adapted varieties are identified, advocates of organic breeding now promote the use of direct selection for many desired characteristics.

    Genetic engineering is a very new science and we have a lot to learn about the good it can do and the damage it can cause. The main concern is that not enough tests are being done to ensure it is safe.