When was the last time you saw three men running down a forest trail（小径）in the rain wearing flip-flops（拖鞋）？That's what my friend Brandon, Josh and I were doing last autumn. We were looking for a waterfall（瀑布）.We didn't have much time to get to the waterfall and back, so we were running. We were wearing flip-flops to prevent our shoes getting dirty.

    It was raining, but lightly. It kept us cool as we climbed over giant stones and through a shallow（浅的）stream. We followed red arrows（箭头）and crossed that stream several times, walking on toward the promised waterfall. Time was not on our side, however, and we were forced to turn around. As we started back, we looked at the shallow stream we had just crossed. Where did this rushing river come from? That was when we realized a flash flood was around!

    In the few minutes the water rose at a fast speed. Now there were no big stones to be seen-only what looked like lumps（隆起）covered with rushing water. We had no choice but to move our way back carefully in the rushing water -in flip-flops. We had crossed the stream not once or twice, but six times in search of a waterfall that we never even reached!

    With most of the crossings, we needed each other's help if we didn't want to be washed away by water. Wet all over, we felt relaxed after we made the last crossing.

    "My dad always told me to keep off a river when travelling in the rain." Josh said as we hurried back down the path.

    "Why didn't you tell us that earlier?" I laughed.

    "Would it have made a difference?" came the reply.

    He had a point.

    Do you suppose Darwin, one of the greatest scientists of all time, really did fools' (傻瓜的) experiments? Or did he do experiments that were so simple and basic (基础的) that other people just thought they were foolish?

    Sometimes, people think they already know the answer to a question or a problem．Sometimes, they really do know an answer, but without thinking it is important．

    Charles Darwin didn't just think he knew something．And, he believed all things could be important no matter how simple they seemed to be．

    Suppose you drop pieces of paper that are of exactly the same size and shape．If you drop them at the same time in the same place, they will fall in the same way．Now make one of the sheets of paper into a tight little ball and let it drop along with the other pieces．What happens? You have done an experiment that is so simple that you might think it couldn't be worth anything．

    But this simple experiment is important．It explains part of our present day understandings of physics (物理学) ideas that were worked out long ago by Galileo and Newton．And these understandings set aside some of ancient Greek (古希腊的) physics．

    The scientist sometimes stops to look at very simple things and to think very hard about them．Even the simplest idea, which we might think is foolish, can shake the foundations (基础) of science．

    At the end of the wedding party for Monica and Nick, Monica's mother gave her a new bank saving passbook (存折) as a present. She advised her to put some money in the bank when they had happy things in their life and wrote them down in the passbook. She told her to keep it as a record of her marriage.

    Monica shared her mother's idea with Nick. The following were their deposits (存款) after some time: 7 February: $300, first birthday celebration for Nick after we got married; 15 April: $500, Monica got a better job;…

    However, after years, they began to quarrel every day. One day Monica told her mother that they could not live together any longer and agreed to divorce. Her mother said, "Just do whatever you want to do. But before that, take out all the money in the passbook and spend it."

    So Monica went to the bank. While she was waiting, she took a look at the passbook record. Suddenly the happiness in the past came up to her mind. She went back home, handed the passbook to Nick and asked him to spend the money before getting divorced.

    The next day, Nick gave the passbook back to Monica. She found a new deposit of $5,000 with the words, "This is the day I notice how much I love you and how much happiness you've brought me."

    My friends and I joined a two-day survival(生存) training course in the mountains. The first day was really1—there was so much to do! Arriving at the campsite, we were divided into groups and given a tent, some food, a2and a compass(指南针). Standing next to a small river, Fanny3 camping in the grassy area nearby. However, our instructor, Mr.Lee, pointed out that it might flood(淹没) if it rained. In the end, we found a4area. Putting up the tent was very hard.5Mr.Lee helped us a lot.

    By the time we had put up the tent,6was really hungry. "We wouldn't have got this hungry if we had brought some snacks." Peter said. We all told him to7complaining(抱怨) and help us start a fire to cook our food8. Realizing we were having trouble making the fire, he finally9.

    The next day started early. Woken by a strange noise. Peter went to see what was 10.

    "Some cows have eaten our breakfast!" he shouted. "That's all because you didn't11the food properly last night." said Mr. Lee.

    Worried that Mr. Lee was angry with us, we tried very hard on our next12— using the map and compass to find a secret location. We made it to the location13the other group did.

    We all felt very proud of14.

    The survival training course was a great15. Now I feel I could survive anywhere!

    My father died when I was five. It was hard on us all. My brother, who is eight years older than me, began to take care of my mother and me.

    He took on more responsibilities than expected. I remember he made sure the rubbish was taken out, and the yard was cleaned. He did on his own, without being told to do so.

    Because of my father's death, mom had to get a full time job. Brother would get me up for school and make me breakfast. While I was eating, he would lay out my clothes, make my bed, and gather my school books up.

    Hand in hand we would walk to the bus stop. As we waited, he would play games my father used to play with me. When we returned from school, we were alone for about half an hour, until mom was home from work. Before I did my homework, he would sit me down with three cookies and a glass of milk. Then he would prepare something for mom to cook dinner.

    Mom would greet us with a hug and kiss. This was our time to have some fun outside. This was my brother's time to be a kid.

    One Saturday in June several years later, my mother and I were at a store where the Father's Day cards were sold. I stared at the cards. Mom said," Cindy, I know this is hard time for you."

   "No, mom. That's not it. Why don't they have Brother's Day cards?"

    She smiled," You're right, your brother has exactly been a father to you. Go ahead to choose a card."

    I did so, and on Father's Day, my mother and I sat my brother down and gave him the card.

    As he read it, I saw the tears in his eyes. Mom said," Son, your father is proud of you, seeing that he raised a good man, and that you do your best to fill his shoes. We love you and thank you."

    "Oh, my God," said Mrs. Kim. "I don't think we will be able to do our lesson today." Children loved Mrs. Kim's science lessons. Josh asked, "Why not?" "Well," began Mrs. Kim, "I had planned to do some measuring today. But I forgot to bring any ruler. We can't measure anything without a ruler, can we?"

    "What are we going to measure?" asked Mathew. "I want you to measure the distance from one side of the classroom to the other side." answered Mrs. Kim. "We could measure it as my dad sometimes does，" said C. J. "He sometimes just puts one foot in front of the other. I guess that's how we find out how long something is. "

     "Let's see whether that will work，"said Mrs. Kim. "Why don't you see how many feet it takes to cross the room, C. J. ？"C. J. began walking from one side of the classroom to the other side. He put one foot down and then put the heel of the other foot at the toe of his first foot. He continued doing this until he crossed the room. "I counted thirty of my feet from one side to the other side, " C. J. said.

     "So you think the room is thirty feet across？"asked Mrs. Jim. "I think someone else should try "said Maddie "just to make sure. ""All right，Maddie "said Mrs. Kim "why don't you try？"