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”.

    Tu Youyou, aged 85, is a medical scientist at the China Academy of Traditional Chinese Medicine. she has just become the first Chinese woman to win a Nobel prize, for helping discover artemisinin, a new kind of medicine known as "Qing-hao-su" in Chinese in 1971 and dihydroartemisinin, used also to treat malaria(疟疾).

    The discovery of "Qing-hao-su" and its use in treating malaria are regarded as the most important breakthrough(突破) in tropical medicine in the 20th century. It is also a major health improvement for people in developing tropical countries in south Asia, Africa, and South America.

    This is the first time her work has been widely recognized in China, and it also marks the first time China has won a Nobel prize in the sciences.The last time a Chinese national won a Nobel Prize was in 2012, when Mo Yan got the literature award.

    Tu also received several medical awards in the past including the 2011 Lasker Award in Clinical Medicine for the same achievements.Tu was the first native Chinese who was educated and works in China to win the Lasker award, too.

    Billy's favorite color is orange. But he can't see what orange looks like. Billy is blind.

    A month after he was born, his mother noticed that his eyes weren't quite as big as a normal baby's. “Billy would never be able to see.” the doctor told his mother. After that Billy's mother began talking to him, describing things she saw outside the window. She described everything to him.

    Billy does not only depend on his mother's descriptions to learn about the world around him. He sees with his cars and his hands, too. He has perfect hearing. When people make phone calls, he can tell the numbers they dial(拨).

    Billy loves computer science. He began teaching himself computer programming when he was just seven years old. His dream school would be Stanford University. He gets top grades in his classes, making that a real possibility.

    “You can't let excuses get in the way of your dreams, and if you do that you can't move forward and reach your goals, “said Billy.

    Four men who would become fathers were in a hospital waiting room while their wives were going to give birth to their babies. The nurse arrived and proudly said to the first man, “Congratulations, sir. You're the father of twins!”

    “What a surprise! Believe it or not! I work for the Minnesota Twins Baseball teams!”

    Later the nurse returned and congratulated the second father on the birth of his triplets (三胞胎).

    “Wow! That's unbelievable! I work for the 3M Company.”

    An hour later, the nurse returned to congratulate the third man on the birth of his quadruplets (四胞胎). Surprised, he only could answer, “I don't believe it! I work for the Four Seasons Hotel!”

    After this, everyone turned to the fourth man who had just fallen down. The nurse ran fast to his side. As he slowly came to himself, they could hear him speak in a very low voice over and over, “I should never have taken that job at 7-Eleven. I should never have taken that job at 7-Eleven. I should never have taken that job at 7-Eleven.”

    There is a hiking trail (远足小径) near Sara's home. The trail begins at the foot of the mountain and leads all the way to the top. One day, Sara and her father planned to go on a hike. Sara had packed lunches earlier that morning. Her lather filled their backpacks with other things and they set out!

    As they started up the trail, Sara's father pointed out many different plants along the trail. He showed Sara the difference between the leaves of an aspen tree and a spruce tree. Sara was glad that her father knew so much! She always learned something whenever they went on a hike.

    "Look over there," Sara said in a low voice. They had just turned a comer on the mountain trail. Lying in the grass next to the trail was a small baby deer(鹿). It looked at them with wide eyes, but it did not move.

    "Where is its mother?" Sara asked. "Do you think we should stay here and watch it?"

    "That's a good idea," answered her dad. "We must not go any closer, though." As they sat down and unpacked their lunch, Sara asked her dad why they couldn't go any closer to the deer. He explained that sometimes, if the mother smelled humans too close to her baby, she would be too afraid to come back. Sara and her father agreed that they would wait for the mother to come back, but that they would not get too close to the deer.

    Soon a larger deer walked slowly up to the baby deer. The mother and baby ran quickly down the trail.

    Sara and her father packed up their things and continued up the mountain. They knew that the deer was now safe.

    Mr. Harris taught sixth-grade science. On the first day of class, he gave us a talk about an animal called" birdcat", which died out during the Ice Age. He passed around a skull（头骨） as he talked. We all took notes carefully and later we had a test.

    When he returned my paper the next day, there was a big red"×" through each of my answers. I failed! There must be some mistakes! I wrote down exactly（确切地）what Mr. Harris had said. Then I learned that everyone in the class had failed. Why? "Very simple, "Mr. Harris said, "I made up all that 'birdcat'. But there had never been any such animal. So the information in your notes was not correct. Did you think you would get good grades for that?"

    However, we felt that was unfair. What kind of a test was this? And what kind of a teacher was he?

    Mr. Harris added, "I have told you many unbelievable things about this animal, such as the size, the color, but none of you have questioned. I hope you will learn something from this lesson. Teachers and textbooks are not always correct. In fact no one is." He also told us not to let our minds go to sleep, and to speak up if we thought he or the textbook was wrong.

    Up to now Mr. Harris' class gave me and my classmates something just as important: to look people in the eye and tell them they are wrong.