When William Brown taught at Boston University, he once thought about the people that he hadn't thanked in his life. They taught him, encouraged (鼓励) him or cared a lot about him.

    Tina Johnson was a teacher. She once taught William geography, and William loved geography all his life. So he wrote a letter of thanks to her.

    He got the teacher's letter later. It began, “My dear Willie”. He was happy. Now over 50, he didn't think someone would called him “Willie”. Here is that letter.

    My dear Willie,

    I cannot tell you how much your letter meant to me. I am in my eighties, living alone in a small room and cooking my own meals. You will be interested to know that I taught school for 50 years and yours is the first letter of appreciation (感激) I ever got. It came on a cold morning and it made me feel very warm.

    ......

    William cried when he read the letter. She was one of the people that William hadn't thanked in his past. She helped him to believe in himself. He would never forget her.

    There are some people we should always remember, because they helped to shape our life. William Brown found a way to show his appreciation—he wrote them letters.

    Who are some of the people that you need to say thank you to in your past? It may be too late to say “Thanks”.

    On March 14, one of science's brightest stars went dark. Stephen Hawking, the world-famous British scientist, died at 78 in Cambridge, UK.

    Hawking is considered by many to be the greatest scientist in history since Albert Einstein. He came up with the theory（理论） that the universe (宇宙) began with the Big Bang and will end in black holes. His theories became the base for a lot of later research. He also wrote books to help common people understand the universe. His most famous book is A Brief History of Time, which has sold more than 10 million copies around the world.

    Besides his scientific achievements, Hawking was also someone who had a strong will. When he was 21, he got a serious illness that stopped him from walking and talking. Later in life, he had to sit in a wheelchair and “speak” using a computerized voice. But this didn't stop him from living a meaningful and colorful life.

    He celebrated his 60th birthday by going up in a hot-air balloon; when he was 65, he took part in a zero-gravity (零重力) flight to experience weightlessness. He hoped to travel into space one day. In 2015, Hawking spoke about how he felt life was unfair when he first knew about his illness. “But now, 50 years later, I can be quietly satisfied with my life,” he said.

    Rachel Carson(1907-1964) was a pioneer of the world's environmental movement through her writing about the protection of the natural world. Her 1962 book Silent Spring made her well known by many people. It describes the harmful changes in the environment of using toxic chemicals (有毒化学物质) on farmland.

    Carson first worked as a biologist in the US Bureau of Fisheries. In 1951, her first book The Sea Around Us came out. It became a bestseller. It made her rich enough to leave her job and spend all her life in writing. She was a talented writer. Her next two books were also about the oceans and both on the top of the book sales lists.

    Carson's book Silent Spring completely changed the way Americans thought about nature. It painted a bleak(荒凉的) future for the whole natural world. It led to a nationwide ban(禁止) on the use of a deadly chemical called DDT, and other toxic pesticides(农药) that farmers used for their crops. Many people say the book led to the creation of America's Environmental Protection Agency.

    Since her death, Carson's name has continued to be connected with protecting the environment. There is now a yearly Rachel Carson Book Prize. Norway gives the Rachel Carson Prize to women who have done a lot on environmental protection. In 1980, 16 years after her death, she was given the Presidential Medal of Freedom, the highest civilian honour in America.

    Once a young man hoped to study law and he wrote to Lincoln for advice, who lived most of his adult life as a practicing lawyer. Lincoln replied, "If you make up your mind to make a lawyer of yourself, the thing is more than half done already. Always keep in mind that your own decision to succeed is more important than any other thing."

    Lincoln knew this because he had gone through it all. He had never, in his life，had more than a total of one year's schooling. And books? Lincoln once said he had walked to borrow every book fifty miles away from his home. A fire was usually kept going all night in the small house and he read by the light of it.

    He walked twenty or thirty miles to hear a speaker and, returning home, he practiced his talks everywhere—in the fields, in the woods, before the crowds. He joined several societies and practiced speaking on the topics of the day.

    Being short of confidence always troubled him. He was shy before women. Even when he was in love with Mary Todd, he used to sit there, nervous and silent, unable to find words, listening while she did the talking. Yet that was the man who, by practice and home study, made himself into a famous speaker with great eloquence(雄辩).

    When he spoke of his own great painful experiences, he wrote, "If you make up your mind to make a lawyer of yourself, the thing is more than half done already."

    Emma and Hannah are 13-year-old school girls from Minnesota, USA. They are good at making new things both of them are also good at sales. They are selling charms (小装饰物) made out of bottle caps.

    The girls came up with the idea last summer when they saw charms were popular with kids. They talked with their parents about the idea. Since then they have sold enough charms to buy a bike for Hannah.

    The girls collect bottle caps and then clean them. They find some interesting pictures on the Internet or on paper, and then glue them onto the inside of the caps. There are different kinds of pictures, "Peace signs are popular with girls, and single-letter charms are popular with boys whose names start with those letters," Emma and Hannah said.

    Now, charms can be found everywhere at Dakota Hills Middle School in Eagan. "Students put charms on purses, backpacks, and their lunch boxes," said Emma. Emma and Hannah also have a shop on the Internet. They hope they can sell their charms to more kids. They're thinking about selling their charms at the Eagan Market Festival next summer.

    Their business is not only for getting money. At their Valentine's sale, 20% of the income (收入) went to charity.