阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。

    There are many useful suggestions that can help one to improve English. Here are some of them to increase one's English language vocabulary.

    Learning English vocabulary is about much more than just learning the right words. It is based on understanding important words and expressions.

    Learning a word will not help very much if you quickly forget it. Researches show that it takes from 10 to 20 repetitions(重复) to really make a word part of your vocabulary. Since most words are learned from how they are used in context (上下文), the more words one is shown, the better vocabulary one will have. Keep a piece of paper close to you. When you read, pay close attention to the word you do not know, write the word down and try to understand its meaning from the context. Then look up the word in a dictionary. 

    Remember that if you do not use English words that you have just learned in conversation or writing, you will forget them very quickly. So the best way to learn new words effectively is just by trying to use them in conversation and writing. Remember also that practice is the key to fluent spoken English.

    Building vocabulary is a life-long task. Remember: ＂In the beginning was the word.＂ Your future could depend on how rich your vocabulary is. It will also determine the quality of your communication.

    Successful People

    People can succeed in many aspects. Here are some successful people.

    Stephen Hawking

    Much more than the namesake of Into the Universe with Stephen Hawking, Stephen Hawking is one of the most well-known physicists in the world, and he was able to achieve that in spite of being diagnosed with ALS when he was 21. He can now only speak with the assistance of a computer and has been a full-time power chair-user since the 1980s. His disability, however, has never been an excuse to give up on his desire to study the universe, specifically the framework of general relativity and quantum mechanics. His best-selling book, A Brief History of Time, stayed on the Sunday Times bestsellers list for a surprising 237 weeks.

    Franklin Delano Roosevelt

    A beloved U. S president who helped guide the nation successfully through World War II, President Franklin Delano Roosevelt is considered a great president and the entire time he was in office, FDR was also a wheelchair-user. Upon starting his political career in excitement, he got illness while drinking water at a campground and became disabled from the waist down. Even though it wasn't made public until years later that he couldn't walk for fear of the public doubting his ability, FDR proved disability wasn't a roadblock to being a great leader.

    Marlee Matlin

    An Academy Award winning actress for her leading role in Children of a lesser God, Marlee Matlin is one of the most successful actresses who are deaf. She has been deaf since she was 18 months old. She also received a Golden Globe Award for her role in Children of a lesser God. Since receiving her Oscar, Marlee has been a character on many TV shows including The Word and Law & Order: SVU, and has appeared on reality shows such as The Apprentice and Dancing with the Stars.

    Steven Wonder

    One of the most beloved singers alive today, Stevie Wonder is a musician, singer and songwriter who was born blind. He was born six weeks early. The blood vessels at the back of his eyes had not yet reached the front and stopped their growth, therefore leading to his blindness.

    Considered a child talent, Stevie signed with his first record label at age 11, Motown's Tamla label, and he's been performing since. Over his wildly successful music career, Stevie has recorded more than 30 U. S. top ten hits, including his singles “Superstition” “Sir Duke” and “ I Just Called to Say I Love You”.

    2017 was an influential year for artificial intelligence (人工智能), not just in terms of the advancement of the technology itself, but also for the development of our understanding of AI's impact on our society.

    When we talk about AI, often we focus on the belief that it is going to take away certain types of jobs. However, we often ignore the fact that this technology will also slowly spread into most of our lives.

    Thanks to the development of AI, we are on the highway of IA, (human) intelligence augmentation (增强). Despite the great steps we've made in AI development and will continue to make in 2018, we are still years away from AI fully replacing human jobs. However, we are much closer to seeing the impact of AI spread into almost every job and the growth in human intelligence.

    Take a doctor for example: AI will soon be able to detect and diagnose common diseases more quickly and accurately than humans. Now, doctors can spend more of their time explaining the possible diagnoses, communicating with patients and developing unique, reliable treatment plans that are most effective for each specific patient.

    However, AI is so powerful and its adoption will only accelerate as it begins to help our work and allow us to focus on the parts of our job that are most important. But part of why AI is so attractive is also why it's so dangerous. That is, that same power allows AI that are making incorrect decisions to do so with greater speed and impact than humans have ever had.

    This is why, as AI becomes more useful in 2018, it will also become more closely examined. 2018 will be the year when companies purchasing AI products don't just ask about the power of AI—they will make sure that it is tested carefully in advance, minimizing their potential unexpected impact.

    Shree Bose is one of the most impressive kids graduating from Fort Worth Country Day High School this year. Bose has a large circle of friends, and there's one who you may have heard of: President Obama. He has twice publicly recognized her achievements in cancer research and spoken with her in the Oval Office.

    If that isn't enough, Bose recently gave a TED Talk about her work with the cancer drug Cisplatin, which also won her first prize at the Google Science Fair and recognition as one of Glamour magazine's Young Amazing Women of the Year.

    After watching her grandfather struggle with liver cancer, Bose was determined to help out in any way she could. As a high school student though, her scientific choices were limited. She reached out to various hospitals and research centers, but doctors turned down her requests because they felt she was too inexperienced medically.

    Only the North Texas Science Health Center respected her determination and chose to guide her. The results were amazing.

    Bose chose to study a protein (蛋白质) and its reaction with the cancer drug Cisplatin. She noticed that when she prevented this protein from growing, Cisplatin was allowed to begin destroying cancer cells once again.

    “My project not only contributes to the understanding of the relationship between the protein and Cisplatin, but also suggests a newer, more effective treatment for patients who resist Cisplatin,” Bose said.

    Bose's achievements aren't limited to the lab, though. She was also captain of her swim team and editor-in-chief of her school paper.

    Bose is currently getting practical experience at the National Institute of Health and she'll be attending Harvard in the fall. She plans to study molecular biology and go to medical school. Eventually, she would like to be a doctor.

    When Cherry Watson travelled on a recent flight from New York to Washington and noticed an 'awful tension' in the cabin, she first thought it was caused by typical bad-tempered passengers. But as the flight neared its end, it became obvious that something was very wrong.

    A teenage boy with Down Syndrome (唐氏综合症) who was traveling with his family had become upset and would not return to his seat, regardless of the cabin crew's warnings over the loudspeaker that it was almost time to land. The pilot was forced to circle above the airport, delaying the landing and angering people on the already tense flight.

    'If it was a cartoon,' remembered Watson, 'there would have been smoke coming out of people's ears.'

    The boy's elderly parents and adult brothers and sisters tried to persuade him to get off the floor and back into his seat, but in vain. Watson, who used to be a teacher, stood up and quickly headed to the back of the plane.

    She found the boy in the passage between rows of seats, lying on his belly, and lay down on her stomach to face him. She began chatting calmly with him, asking his name, his favorite book, and his favorite characters. He told her he felt sick and she tried to comfort him.

    Minutes later, he allowed her to hold his hand, and then together they got properly back into airplane seats. Watson asked for sick bags, and held them as the boy threw up several times, including on her. As she helped him clean up, she repeatedly told him everything would be okay and that they'd get through it together.

    After the plane was finally able to land, no one was impatient to step off the flight as one might expect. Instead, calmed passengers—obviously following Watson's amazing example—allowed the boy and his family to depart first, smiling at them as they passed. His parents tearfully thanked Watson for what she had done, and a doctor sitting nearby also let her know he had even taken notes on her expert way of handling the situation.

    Retired jet engines could help clear the smog that smothered big cities.

    To land at Indira Gandhi Airport is to descend from clear skies to brown ones. New Delhi's air is poisonous. According to the World Health Organization, India's capital has the most polluted atmosphere of all the world's big cities. The government is trying to introduce rules that will curb emissions-allowing private cars to be driven only on alternate days, for example, and enforcing better emissions standards for all vehicles.

    But implementing these ideas, even if that can be done successfully, will change things only slowly. A quick fix would help. And Moshe Alamaro, a researcher at the Massachusetts Institute of Technology, thinks he has one. His idea is to take a jet engine, put it next to one of India's dirty coal-fired power plants, point its exhaust nozzle at the sky and then switch it on. His hope is that the jet's exhaust will disrupt a meteorological phenomenon known as "inversion", in which a layer of warm air settles over cooler air, trapping it, and that the rising stream of exhaust will carry off the tiny particles of matter that smog is composed of. Inversion exacerbates air pollution in Delhi and in many other cities, from Los Angeles to Tehran. A particularly intense example caused the Great Smog of London in 1952, when four days of air pollution contributed to 12,000 deaths.

    Dr Alamaro thinks a jet engine could punch through the inversion layer to create a "virtual chimney" which would carry the trapped pollution above it, so that it could be dispersed in the wider atmosphere. He calculates that all the emissions from a gigawatt coal-fired power plant could be lifted away using a single engine with a nozzle speed of 460 metres a second.

    However, he has not calculated whether a jet engine could disrupt the inversion layer and allow the pollution to escape the city-so he is now going to test that hypothesis. Within eight months, Dr Alamaro plans to put one of his updrafters next to a coal-fired power plant and monitor what happens using a fleet of drones. He is in discussions with Tata Group, a conglomerate with an electricity-generating arm, to run it next to one of the firm's power stations.